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2020 | Book

Proceedings of the International Conference of Sustainable Production and Use of Cement and Concrete


Editors: Prof. Jose Fernando Martirena-Hernandez, Prof. Adrian Alujas-Díaz, Prof. Meylin Amador-Hernandez

Publisher: Springer International Publishing

Book Series : RILEM Bookseries


About this book

This volume gathers the latest advances, innovations and applications presented by leading international researchers and engineers at the International Conference on Sustainable Production and Use of Cement and Concrete (ICSPCC 2019), held in Villa Clara, Cuba on June 23-30, 2019. It covers highly diverse topics, including sustainable production of low-carbon cements, novelties in the development of supplementary cementitious materials, new techniques for the microstructural characterization of construction materials, Portland-based and alkaline-activated cementitious systems, development of additives and additions in the sustainable production of concrete, sustainable production of high-performance concrete, durable concrete produced with recycled aggregates, development of mortars for historical patrimony restoration, environmental and economic assessment of the production and use of cement. The contributions, which were selected by means of a rigorous, international peer-review process, highlight numerous exciting ideas that will inspire novel research directions and foster multidisciplinary collaboration between different specialists.

Table of Contents



Considerations for the Energy Balance and Preliminary Design of an Experimental LC3 Cement Pilot Plant

Associated with cement manufacturing processes, large amounts of carbon dioxide (CO2) are released into the atmosphere, it is estimated that between 0.65 and 0.90 tons of CO2 are emitted per ton of cement manufactured. By 2050, the demand for this binder is expected to exceed 5000 million tons, which would contribute to an increase of more than 3% of emissions. However, the emissions can be reduced by using supplementary cementitious materials (SCM), in this sense the calcined clays have a great potential for the reduction of emissions in the manufacture of cement, has been studied in recent years’ low carbon cement or LC3, developed by a joint team of the University of Lausanne and the Central University of Las Villas. The main results are the expansion of production by achieving clinker substitutions of up to 50%. In this sense, the Center for Research and Development of Technologies and Materials (CIDEM) in conjunction with the company IPIAC-NERY has committed to the development of a small pilot plant that makes the manufacture of limited quantities of LC3, which allows the study of the process by interacting different sources of raw materials. In this paper some calculations were for designing a pilot plant, taking into account the balance of mass and energy necessary for its proper functioning, which in turn allows to specify the technology for the scaling of the production in any new industrial plant or adaptation of capacities installed.

Ivan Machado-Lopez, F. Bacallao, I. H. Moya, Jose Fernando Martirena-Hernandez
Use of Grinding Aids for Grinding Ternary Blends Portland Cement-Calcined Clay-Limestone

This article presents the evaluation of three types of grinding intensifier additives which were used for the production of LC3 cement, as well as the addition of LC2 minerals, treated in a laboratory scale ball mill. For its analysis a group of research techniques were applied to study its effect on the rheological and physical—mechanical properties of LC3 cement and LC2 mineral addition. The results of the work indicate that the milling intensifier additives evaluated have a positive impact on the mechanical properties of the samples evaluated, with a slight increase in the water—cement ratio caused by an increase in fineness.

Juan Francisco Garcés Vargas, Marlon Espinosa, Yosvany Diaz Cárdenas, Alina Hereira Diaz, Jose Fernando Martirena-Hernandez
Effect of the Addition of Calcined Clay-Limestone-Gypsum in the Hydration of Portland Cement Pastes

Currently, mineral additions are widely used as they favor not only the partial replacement of Portland cement, they reduces clinker production, but also provide certain chemical and physical properties that make concrete more durable. The variation of the water-cement ratio, the use of setting retarding additives and the addition of Cementitious Supplementary Materials (MCS) are factors that have a great influence on the hydration of the cement and the formation of the phases of a hydrated cement paste. That is why this research focuses on evaluating the effect of the active mineral addition of calcined clay, limestone and gypsum (LC2), in the cement hydration process. The work consists of several stages: first, a study is made of the variations that are made to the water to define the protocol and the amount of addition to study (30%); In a second stage, calorimetry and chemical shrinkage tests are carried out on cement pastes and a final stage where the influence of the addition on the hydration processes of the pastes is analyzed. This research provides a way of replacing Portland cement through the use of mineral additions, as is the case of LC2, which are in turn within the Construction Industry, to be a sustainable way of production of materials in Cuba.

María B. Díaz García, Lyannis Aparicio Ruíz, Jose Fernando Martirena-Hernandez
Influence of Limestone Content and PSD of Components on Properties of Clinker-Calcined Clay-Limestone Cements Produced by Intergrinding

This paper looks at the study of intergrinding for the production of ternary cement based on clinker, calcined clay, limestone and gypsum with 50% of clinker substitution (LC3). The impact of grinding time on clinker, limestone and calcined clay PSD, and how this parameter influences the overall performance of the ternary cement is assessed. Laboratory cement blends were produced by grinding all components in a batch laboratory mill. Industrial cements produced through intergrinding in a continuous ball mill were used for comparison. Three fractions were identified: d < 7 µm, 7 µm < d < 40 µm and d < 40 µm, for each of the cements studied and the amount of each component were assessed. Fresh and hardened state properties of blends were tested. Results indicate that in intergrinding most of clinker remains at the medium fraction, and further grinding cannot improve clinker fineness due to fine calcined clay muffle clinker fineness gaining. PSD of limestone and calcined clay is wider than clinker PSD, with a high amount of each material on fine fraction, having a strong impact on rheology. A change in calcined clay/limestone ratio from 2:1 to 1:1 improves clinker grinding and rheology but has a negative impact on strengths due to the less proportion of calcined clay that impact negatively on the pozzolanic reaction.

A. Pérez, Jose Fernando Martirena-Hernandez
Influence of the Limestone Type on the Compression Strength of LC3 Cements

This article aims to study the influence of the CaCO3 content of the limestone filler on the compressive strength of LC3 cements. In order to perform this study, the compressive strength test was performed in LC3 cements containing three types of limestone (A, B and C) with different CaCO3 contents. To characterize the materials, tests were performed as X-ray diffraction, X-ray fluorescence, particle size distribution and BET surface area. Three different types of cements were created, varying the type of limestone filler. All blends contained 50% clinker, 5% gypsum and 30% calcined clay and 15% limestone. Characterization tests found that the filler A presented the highest amount of CaCO3, while the filler B presented medium content and the filler C, low content. The results of the compressive strength showed similar values between the A and B fillets at 28 days and higher results for the filler B at 91 days. Filler C obtained lower scores at all ages. From this, it was possible to conclude that the CaCO3 content of limestone influences the compressive strength of LC3 cements.

Felipe Tarquinio Oliveira, Christian Moreira, João Henrique da Silva Rêgo, Valdirene Maria S. Capuzzo
Pozzolanic Reactivity of the Calcination Products Obtained from Yaguajay Clay Deposit

The influence of calcination temperature and mineralogical composition on the pozzolanic reactivity of calcination products obtained from Yaguajay clay deposit is assessed in this research. The samples were characterized by ATG, DRX and petrography. The pozzolanic reactivity of calcination products was evaluated by compressive strength (NC95:2011, NC506:2013, NC-TS527:2013, NC-TS528:2013) and its influence in the hydrate kinetics by isothermal calorimetry in pastes with 30% of cement substitution for calcined clay. All identified technological types present quartz, calcite, goethite and kaolinite like main mineral phases. The kaolin contents oscillate among 40% (Types A and B) and 50% (Type C). The calcite contents are lower than 5%; except in the layer B, with 20%. The pozzolanic reactivity of the calcination products of all the technological types is strongly influenced by the activation temperature, being reached the best reactivity at 800 °C. Other factors that could affect negatively the pozzolanic reactivity are high calcite contents (Type B) and high contact degree between the calcite and the kaolinite (Type C). For a sustainable exploitation of the deposit, it is recommended that the composite dedicated to the industrial production has an approximate composition of 37.5% Type A, 25% Type B and 37.5% Type C.

Karina Duverger Escobar, Adrián Alujas Díaz, Luis Alberto Pérez García
Mechanical Strength Analysis of Ternary Cement Pastes Containing Nanosilica and Metakaolin

Supplementary cementitious materials’ (SCM) usage in cement based composites is increasing in construction, aiming to improve performance, sustainability and cost of those materials. Among those SCM’s, Metakaolin (MK) and Nanosilica (NS) have been studied by many authors with interesting results, usually an increase in mechanical strength and microstructure refinement. However, the combined use of those two in a ternary mixture with Portland cement was studied by few authors. The present work aims to evaluate this type of mixture through an analysis of compressive strength of 6 different mix proportions. The mix proportions used were a reference paste with 100% Portland cement, two pastes with 1 and 2.5% replacement of clinker by Colloidal Nanosilica and three pastes with 15% replacement of clinker for complementary contents of NS and MK (0 + 15%, 1 + 14% and 2.5 + 12.5%). The compressive strength tests were performed at 1, 3, 7 and 28 days of hydration. The results were analyzed by statistical methods, such as ANOVA test and Duncan Test. At early ages, the use of nanosilica increased the compressive strength. The ternary mixtures presented the highest strength values at 7 and 28 days, and a synergistic effect between these SCM’s was observed at 7 and 28 days, for the 12.5MK2.5NS paste.

Matheus Ian Castro Sousa, João Henrique da Silva Rêgo
Hydration of Cement Pastes Using the Cement LC3

Nowadays, cement is still one of the most consumed products in the world, and has grown more significantly. Thus, the use of supplementary cementitious materials (SCMs) to some extent reduces the carbon dioxide (CO2) emissions in the environment, contributing to the formation of a sustainable cement. In this context, Limestone Calcined Clay Cement (LC3) has a mechanical performance similar to the ordinary Portland cement (OPC). This work aims to analyze the evolution of the hydration of the LC3 cement in comparison with the reference cement, according to the existing materials in Brazil. For this, the characterization of Portland cement of high initial resistance (CP V-ARI), metakaolin, and limestone filler was carried out. Pastes with a 45% substitution of Portland cement by these SCMs were prepared in a ratio of 2:1, with 30% of the metakaolin and 15% of the limestone filler. Pastes were prepared according to ABNT NBR 16606 [8] in water/binder ratio of 0.40. To follow the hydration, the X-ray diffraction (XRD) assays were performed, at the ages of 1, 3 and 7 days. The results indicated a change in the formation of the hydration products of the LC3 cement compared to the reference paste over the ages.

Myrelle Y. F. Câmara, Yuri S. B. Fraga, Valdirene M. S. Capuzzo
Potentialities of Different Materials from the Eastern Region of Cuba as Partial Cement Substitutes: A Comparison of Their Performance

The prospects for the use of supplementary cement materials depend to a large extent on their potential and their availability. In this work, the potentialities of three materials (calcined clays, zeolitized tuffs, vitreous tuffs) as sources of supplementary cementitious materials are presented. Each material was characterized from the chemical and mineralogical point of view. The reactivity was determined in standardized mortars and their behavior was assessed in mixed cements and hollow concrete blocks. Based on the results obtained, a comparison between the performances was made. The best results were shown by the calcined clay, followed by the zeolitized tuff and vitreous tuff, which corresponds to the reactivity of each material.

Roger S. Almenares Reyes, Adrián Alujas Díaz, Carlos A. Leyva Rodríguez, Lisandra Poll Legrá, Yosbel Guerra González, Luis A. Pérez García, Sergio Betancourt Rodríguez, Jose Fernando Martirena-Hernandez
Production of Limestone-Calcined Clay Cement in Guatemala

This work describes the production process for the first formulation of a limestone-calcined clay cement in Guatemala, with a total production of 160 metric tons of cement. After reviewing more than 10 possible sites for extraction of clays at several regions, that could accomplish the criteria for usage as an activated clay material, a 67% of kaolin content material was finally selected, on a location around 50 km of our cement factory. With the selected material, a theoretical formulation by weight was defined of 48% clinker, 30% calcined clay, 17% limestone and 5% gypsum, the process began with the thermal activation of the clay, by passing 125 tons of raw material by a rotary kiln at 750–850 °C, temperature control was possible due to a series of control points using a thermal imaging camera, the activation process was controlled by X-Ray Diffraction, looking for the reduction of the signal for kaolin type clays, obtaining 90 tons of activated material. The cement produced had a 48% of clinker content verified by XRD, around 12% lower than any general use cement produced in the country. This cement was tested for strength development, setting time, hydration heat, and alkali-silica reactivity showing a very good performance. No critical difference was perceived between the concrete produced with the new cement and one with 83% of clinker with similar strength performance at 28 days evaluated by ASTM C39. The mortar, developed a superior strength compared to the national normative for a general usage cement ASTM C1157.

S. Torres, E. García, L. Velásquez, R. Díaz, Jose Fernando Martirena-Hernandez
Processing of Calcined Clays for Applications in Cementitious Materials: The Use of Grinding Aids and Particle Classification After Grinding

Calcined clays provide a promising opportunity to lower clinker levels in cements because of their widespread availability and their excellent reactivity in blended cements. On the other hand, one of the main drawbacks of calcined clay utilization for blended cement manufacture is the negative impact on workability. This project explores the use of grinding aids to control the resulting particle size distribution of calcined clay and limestone. It was observed that after grinding, calcined clays exhibit a strongly bimodal particle size distribution, where the clay minerals concentrate mainly in the finer particle population. Particle classification (air separation) techniques were applied to remove the impurities (mainly quartz and iron oxides) and therefore, increase the amount of kaolinite in the resulting material. An increase in the kaolinite content from 29 to 45% by mass was achieved in one step and without pre-dispersion of the particles.

Franco Zunino, Karen L. Scrivener
First Experiences with Geopolymeric Mortars of Alkaline Activation Based on Natural Pozzolans

The geopolymers are a new class of inorganic polymers that are obtained from the alkaline activation of natural minerals or industrial wastes and by-products. In the present investigation we describe the destructive and non-destructive tests carried out on the mortars made from the alkaline activation of the natural pozzolans from the Las Carolinas deposit to measure mechanical and durability properties. For this purpose, sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as alkaline agents. The results were analyzed through an experimental methodology where variables such as alkaline solution and curing time were determined. Finally, the mortars were analyzed mechanically, where their compressive strength was determined at 7 and 28 days of age, and their durability was also evaluated from the measurements of electrical resistivity and ultrasonic pulse velocity. The results obtained were compared with the values specified by the Cuban standard regarding the properties of mortars, also revealed that the pozzolanic material used as source of pure aluminosilicate has low alumina content, which affects the low mechanical resistance of the mortars The final product presents a series of properties that demonstrate the potential of natural pozzolans as a cementing material, which does not have any type of industrial process, or additives, or CO2 emissions during its use, the main reason for this research.

Joaquín Raúl Cuetara Ricardo, Rolando Batista Gonzales
Surfaces of Response. An Effective Methodology to Estimate the Optimal Factor k of the Supplementary Cementitious Materials

Pozzolanas of natural origin have been widely used in the manufacture of mortars and concrete for millennia, from the ancient Greek and Roman civilizations to the present. In the present work, the k-factor of the natural pozzolans of the Western region of Cuba is studied and its influence on the quality of the concretes is evaluated. The response surface methodology was used to locate the optimal replacement values. In the design of the experimental program, the determination of the resistance to compression at 7 and 28 days, and the effective porosity at 28 days were conceived. The study showed that, according to Cuban regulations, the factor k of these pozzolans is 0.2, however, with the use of the proposed methodology it was possible to optimize the replacement levels and the curing time.

Joaquín Raúl Cuetara Ricardo
Determination by Ultraviolet-Visible Spectroscopy of Adsorption of the Superplasticising Admixtures Dynamon SX 32 and Dynamon SRC 20 in Calcined Clay of Layers A, B and C of the Yaguajay Deposit and the Pontezuela Deposit

This work proposes the ultraviolet–visible molecular absorption spectroscopy as method of chemical–physical analysis, simple and economically viable for Cuba, for the sake of quantifying the superplasticizers adsorption in calcined clay. The superplasticizers Dynamon SX 32 and Dynamon SRC 20 were rehearsed (commercial name of the signature MAPEI), used in the industry of the construction in the country and four roasted clays of the locations of Yaguajay (3) and Pontezuela (1). Firstly the spectra were obtained for both superplasticizers and the longitude of wave for work was selected; then the calibration straight line were elaborated for the quantitative analysis and lastly, the method was proven in the four clays. For both superplasticizers the longitude of selected wave was 259 nm. The calibration straight line presented superior determination’s coefficients to 0.995 and variation’s coefficients for point inferior to 3%. The adsorption of the superplasticizers in the roasted clays oscillated between 40 and 60%. The results demonstrate the feasibility of using the method proposed for the analytic determination as well as the strong adsorption that these superplasticizers present in the roasted clays for the studied systems.

Alina Hereira Díaz, Roger Castillo Delgado, Adrián Alujas Díaz
Effect of Gypsum Content on the Compressive Strength of LC3 Cement

Due to environmental damage caused by the Portland cement manufacturing process, industry and academia have been required to reduce greenhouse gas emissions from the production process. The massive use of supplementary cimenticious materials (SCM’s) is one of the most viable options for reducing clinker factor and pollutant emission. LC3 cement is a type of cement that uses high additions contents, counting on the synergistic reaction between calcined clay and limestone to obtain mechanical strengths similar to those of traditional cements. This research intends to investigate the influence of the gypsum content on the compressive strength of a LC3 cement. For the accomplishment of this study six mortars were produced. In three of them the cement used was produced with 3, 5, 7% gypsum, without SCM’s. In three mortars, a 45% replacement cement was used (30% calcined clay and 15% limestone). The proportion of gypsum in these cements was 3, 5 and 7% in relation to the total mass. For the hardened state analysis, the compressive strengths were compared at the ages of 1, 3, 7, 28 and 91 days. A statistical analysis was performed on the results. From the results obtained it was possible to verify that the gypsum content influences the compressive strength of the LC3 cement. The highest mechanical strengths were obtained with the use of larger quantities of gypsum.

Christian Moreira, João Henrique Silva Rêgo
Experimental Pilot Plant for Low Carbon Cements Development: The Cuban Innovative Project

A new type of pilot plant for research and production of supplementary cementitious materials (SCMs) and others highly reactive pozzolan blends, has being constructed at the Central University of “Las Villas”, with Swiss cooperation and technical support of IPIAC Nery. The raw materials: low grade kaolinite clays, limestone, clinker and gypsum are available in many geological settings, at low cost, and have the quality required for building admixtures production. Technological flow is quite simple, with eleven steps, and great level of mechanization and automation according to process needs. Pilot scale equipment was designed and constructed on the basis of European standards. Drying and calcination of clays, with a feed rate of 100–300 kg/h, is carried out in a rotary horizontal diesel fired kiln, at temperatures between 600 and 850 °C. Grinding, blending and homogenization of cement components is carried out at a rotary balls mill, and a centrifugal blower fan send the final product to a centrifugal solid gas separator, getting ready for packing and storage. The technical and operational facilities of this pilot plant offers a great innovative potential that will be used for academic, investigative and educational purposes, contributing additionally to materials production local programs development, a national priority.

G. Esperanza, Ivan Machado-Lopez, Jose Fernando Martirena-Hernandez
Ultrasonication Effect of Silica Fume on Compressive Strength of Cement Pastes

Portland cement production is responsible for about 6–8% of the world’s CO2 emissions. To reduce this emission, several researchers have studied the replacement of clinker by highly reactive supplementary cementitious materials such as rice husk ash, metakaolin and silica fume in the production of high performance cementitious materials. In these studies, it was verified that the silica fume agglomerates due to the small size of its particles and with that its reactive potential is reduced. Thus, the objective of this research is to verify the ultrasonication effect of silica fume on the mechanical performance of cement pastes. Three cement pastes were studied, a reference with 100% Portland cement CP V-ARI and two with 10% substitution of the Portland cement by silica fume, one in its natural state and the other ultrasonicated. It was prepared 12 test specimens for each trait by setting the scattering at 140 ± 10 mm in the mini slump test. Three specimens were ruptured at 1, 3, 7 and 28 days of hydration. With the results, a statistical analysis ANOVA was performed through the Duncan’s test in Statistica v10 software. Through the results, it was verified that the ultrasonication of the silica fume increased its reactive potential and consequently its mechanical performance. Thus, by ultrasonication of silica fume it is possible to produce high-performance cementitious materials with lower consumption of Portland cement and consequently reduce the emission of CO2 into the atmosphere.

Yuri Sotero Bomfim Fraga, João Henrique da Silva Rêgo, Valdirene Maria Silva Capuzzo
Influence of Fixation of Consistency or Superplasticizer Content on Strength of Cement Pastes with Silica Fume or Nanosilica

Currently, the production of pastes, mortars and concretes with replacement of Portland cement by highly reactive cementitious materials to reduce the environmental impact caused by cement production is studied. Among these materials, silica fume and nanosilica stand out due to their properties that improve the mechanical performance and durability of pastes, mortars and concretes. Most of the research involving these materials uses superplasticizer to fix the consistency of the researched material. Despite this, there are researches that fix the superplasticizer content in their research. Thus, the objective of this research is to verify the influence of the fixation of the consistency or the superplasticizer content on the mechanical performance of cement pastes with silica fume or nanosilica. For this, five specimens were studied replacing Portland cement by 2% of colloidal nanosilica or 10% of silica fume. The specimens were molded by fixing the superplasticizer content or fixing the consistency of the pastes by the mini slump test. The compressive strength of three specimens at 1, 3 and 7 days was verified. The results showed that when incorporating silica fume or nanosilica in Portland cement, it became difficult to mold the pastes when the superplasticizer content was fixed, which influenced its mechanical performance. In order to carry out research with replacement of Portland cement by highly reactive cementitious materials for the production of pastes, mortars and concretes, it is recommended to fix the consistency of these materials.

Yuri Sotero Bomfim Fraga, Lucas de Paula Vasques, João Henrique da Silva Rêgo, Valdirene Maria Silva Capuzzo


The Effect of Various Superplasticizers on Ultra High Strength Concrete

Ultra-High Strength Concrete (UHSC) is a high-strength and highly ductile material formulated to provide compressive strengths exceeding 130 MPa. UHSC materials typically have a very low water-to-cementitious ratio (w/cm), which requires the use of superplasticizers, also known as High Range Water Reducing Admixtures (HRWRA), to disperse the fine particles and to make the material workable for placing, handling and consolidating. Common examples of superplasticizer compositions include Polynaphthalene Sulfonate (PNS), Polymelamine Sulfonate (PMS) and Polycarboxylate Ether (PCE) based polymers. This study focuses on assessing the impact of various superplasticizers on the performance of UHSC. Four different types of superplasticizers were used; two different PCE based superplasticizers from a leading manufacturer, one PNS superplasticizer, and one PCE superplasticizer, both of which were provided by a local chemical provider. Specific properties assessed were the superplasticizers’ viscosity, concrete workability through the mortar-spread test, and 7, 14, and 28 day compressive strengths. Two mixtures were produced with two w/cm (0.20 and 0.15), which would subsequently increase the amount of HRWRA needed, from 34.7 to 44.5 L/m3. The results show that both name bland PCE superplasticizers produce a higher spread and a higher compressive strength at all ages tested up to 28 days than the two local superplasticizers. Additionally, the rheology test demonstrated that the name brand PCE superplasticizers had a lower viscosity at all angular speeds than the local superplasticizers counterparts.

Anthony Torres, Federico Aguayo, Srinivas Allena, Michael Ellis
Can Sustainability of Concrete Construction Be Improved Through a Better Understanding of Field Practices? Lessons from Haiti

This work is the result of the first collaborative investigation between the National Laboratory for Building and Public Works in Haiti, the Ecole Polytechnique Fédérale de Lausanne and the Swiss Agency for Development and Cooperation on the construction practices with concrete. We have set up the first practical method combining material science to socio-economics to quantify and analyze the actual practices with concrete in the field. We have collected and analyzed real concrete samples randomly selected in ordinary environment in the urban area of Port-au-Prince and recorded qualitative data on the local concrete practices. The results of the first field study are promising for both cement and concrete research and sustainable development of the construction. Approximately 30% of the concretes combine good strength and remarkably low CO2 impact, indeed lower than concrete made in developed countries. This suggests that there is a tremendous potential to make robust and low CO2 concrete around the world in no standardized conditions. Besides this promising perspective, the analysis of actual concretes showed that the most common wrong practice was the excessive use of water in the concrete mix. Nevertheless, these concretes with extreme (w/c) ratio revealed new insights on the cement hydration mechanisms.

Elise Berodier, Loic Aron, Judith Princeton, Ivan Bartolini
Production of Durable Concrete with a Mineral Addition Blend of Calcined Clay-Limestone-Gypsum (LC2) and Portland Cement

This article presents the evaluation of different concrete formulations produced with LC3 cement and LC2 mineral addition. The same includes studies of the properties of fresh and hardened concrete and a preliminary evaluation of its durability. LC3-50 2:1 cement-milled by intergrinding was used, Atenas Cements were combined with LC2 mineral addition, 90% Atenas Cement with 10% SikaFume. Atenas Cement, produced industrially at the Cuenca Ecuador plant, was used as a reference and the concrete was formulated for a dosage of certified concrete, for resistance of 35 MPa.

Juan Francisco Garcés Vargas, Flavio Morocho Guamán, Yosvany Diaz Cárdenas, Alina Hereira Diaz, Jose Fernando Martirena-Hernandez
Behavior of Retraction in Fluid Concretes Produced with Active Mineral Addition LC2

The Supplementary Cementitious Materials (MCS) are currently, together with the additives, the most sustainable solutions that are worked to achieve high performance concrete and more resistant to aggressive environments. This research focuses on the introduction of additions in the hotel buildings of Cayo Santa María, Cuba. With previous studies showing that some additions can decrease the appearance of cracks due to retraction, a phenomenon very common in the coastal areas of the country, it is decided to begin a research focused on tackling cracking of concrete. The aim is to evaluate the introduction of LC2 (calcined clay, limestone and gypsum) as an active mineral addition concrete. The work is divided into two stages in order to evaluate the introduction of LC2 as an addition. In the first stage, the protocol a of the research is defined, the work is specified with 30% addition, in the second stage the tests are carried out to determine the properties of the fresh concrete as a consistency by the Cone de Abrams, in state hardened, resistance at 7 and 28 days and retraction by ASTM C-157. In this way, a study is made available on the effect of the LC2 addition on the properties of fluid concretes and it is possible to reduce the consumption of cement so harmful to the environment, as well as to make available to the construction a new affordable material in Cuba.

María B. Díaz García, Reidel Groero Peña, Liset Quesada González, Jose Fernando Martirena-Hernandez
Behavior of Concrete Made with PP-35 Cement in the Province of Cienfuegos

The problem is derived by the start of the production of PP-35 cement in the Cienfuegos province and the need to know its performance in premixed and precast concrete mixtures, produced with aggregates from this province. Thus, the objective is to characterize the behavior of concrete made with PP-35 cement, to assess its possible application in the prefabricated industry and pre-mixed concrete, with the use of aggregates from the Cienfuegos province. The methodology followed in the work was carried out experimentally in laboratory conditions, evaluating the behavior of the resistance, sorptivity and effective porosity, when the water/cement ratio varies (0.7–0.72). At the same time, this same process was carried out for the cements P-35 and PP-35, achieving a comparison of the behavior models in the three types of cement. The results show that for equal water/cement ratios does not significantly change the resistance of concrete at 28 days when the type of cement used changes, on the other hand, pozzolanic cements improve the sorptivity and porosity compared to cement P-35. The studies allowed to reach the conclusions that it is feasible to use PP-35 cement in the production of premixed concrete and in the prefabricated industry, provided that water-reducing additives, retarders and industrial tests and corrections are used for their application in practice.

Sergio Betancourt Rodríguez, Betsy Hoyos Rodríguez, Camilo González Díaz
Assessment of Addition of Calcinated Clay-Limestone-Plaster to Ordinary Portland Cement in Brickwork Mortars

The present research work includes the influence of the LC2 pozzolanic addition in the behavior of type II brickwork mortars from a series of mechanical-physical tests according to specifications established by the 175:2002 Cuban Norm (NC). This addition is made up of 60% calcinated clay, 40% limestone and 10% plaster. The analysis of the LC2 addition behavior in the brickwork mortars was the result of an experimental design in which the definitions of dependent variables according to mortars properties in their different states, as well as independent variables under the analysis of factors, such as: cement volume, lime and addition to be used, were considered. Raw-materials were characterized and forty-eight 40 mm × 40 mm × 160 mm prismatic test tubes for the water-absorption-by-capillarity and flexo-compression tests were elaborated. In the case of adhesion strength by traction, ceramic slabs were used as support. The analysis of the results allowed the satisfactory validation of the use of the LC2 addition in brickwork mortars according to Cuban Norm specifications.

Dania Betancourt Cura, Jose Fernando Martirena-Hernandez
Concrete Manufactured with LC3 Following the Cuban Standard NC 120: 2014

As part of the development strategy of the LC3 in Cuba, a procedure is developed for the preparation of concretes with different doses (H1, H2, H3, H4) according to the levels of atmospheric aggressiveness established in NC 120: 2014 “Hydraulic concrete—Specifications Concretes will be made that respond to three designs of mixtures where parameters such as cement content and water/cement ratio vary according to what is established in the aforementioned standard. The rheological and physico-mechanical behavior of concrete will be evaluated in a fresh and hardened state, for which the following tests will be carried out: Determination of the slump by the cone of Abrams and the strength of the hardened concrete at 3, 7 and 28 days of curing. The concretes will be made with low carbon cement (LC3) up to 50% replacement of the clinker, calcined clays and limestone, and the patterns, made with Portland cement 35 (P35). Curing influence for the H1 series will be evaluated in both standard and LC3 manufactured concretes.

Eilys Valdés Alemán, Viviana Rodriguez Rodriguez, Jose Fernando Martirena-Hernandez
Evaluation of the LC3 to Be Used for the Local Production of Materials in Cienfuegos

The high demand for binders in Cuba as a result of the constructive needs of a developing country and the unavailability of pozzolans determined that specialists from the Center for Research and Development of Structure and Materials (CIDEM) of the Central University “Marta Abreu” of Las Villas, together with a technical team from the Federal Institute of Technology of Lausanne, Switzerland, will elaborate a proposal of ternary cement based on the substitution of elevated quantities of clinker by a combination of calcined clay and calcium carbonate, a formulation known internationally as LC2 and/or LC3. In this work the use of the pozzolanic addition is evaluated in a workshop of local production of construction materials in the Cienfuegos province, the suitability of the aggregates usually used in relation to the national standards and its relation with the resistance for manufactured concretes is determined with the new type LC3 binder. Results are exposed in the manufacture of small format elements such as hollow blocks with the use of concretes designed and tested in a specialized laboratory of the Ministry of construction, resistance levels higher than 5 MPa are obtained in correspondence with the national standards.

Ariens Laritza Yrigoyen Acosta, Gercier Amaniel Gradaille, Ivan Machado-Lopez
Using a Physical Model Based on Particle Mobility for Mix Design of Commercial Concretes in Order to Increasing Eco-Efficiency

Concrete greenhouse gas emissions are mostly from cement. A relevant strategy for the concrete greenhouse gas emissions abatement is the increase of the efficiency in the use of its binder. For this, it is important to understand the packing and the mobility of the concrete particles and their effects on its rheological behavior in the fresh state and the mechanical properties in the hardened state. Currently, the mix design methods are empirical, as opposed to this experimental optimization, the computational optimization emerges, based on predictive models. Thus, the objective of the study is to use the physical model based on particle mobility to predict the rheological behavior of commercial concretes. The method consisted in the following steps: characterization of raw materials; eco-efficiency analysis of 60 formulations of a concrete plant using the binder intensity concept; and a parameter estimation for a descriptive model of slump in function of mobility variables. These concrete formulation binder intensities were between 7.5 and 10.5 kg/m3/MPa, in which the rise of specified fck and maximum aggregate size have a positive impact on this index, while the slump growth has a negative effect. For the base formulations, the mobility variable MPT (Maximum Paste Thickness) showed good correlations with the specified slump (R2 0.99), as well as the model presented a good adjustment to the data (R2 0.94). These results allow an improvement in the mix design methodology using computational optimization, which can lead to an increase on the eco-efficiency of the commercial concretes.

Mariana Menezes, Rafael G. Pileggi, Markus Rebmann, Carlos Massucato
Influence of Temperature and Co2 Partial Pressure on Carbonation Curing for Cement-Free Steel Slag-Based Materials

Sustainable development requires alternative possibilities for industrial sector and green binders are feasible solution for construction industry due their environmental impact reduction by valorising waste, reducing energy consumption and the use of natural resources in production process. Steel slag carbon dioxide activated binder is a cement-free construction material which consumes low amount of water and stores CO2 through its activation. The effect of temperature and CO2 partial pressure on the carbonation reaction was studied aiming to reach optimal conditions to achieve more desirable mechanical properties for the carbon dioxide activated binder. A Portland cement paste under the achieved optimal carbonation conditions were designed to compare compressive strength and reaction products which were determined by thermogravimetric analysis and scanning electron microscope. An electric arc furnace slag from the national steel industry in Portugal and a Portland cement CP-I were used as binders. This work shows the compressive strength development of a steel slag-based binders under 40, 50, 60 and 70 °C of temperature and 0.5, 1.5 and 2.5 bars of CO2 partial pressure on the carbonation curing. Portland cement and steel slag binders had similar compressive strength development and reaction products which were mainly calcium carbonates and calcium silicate hydrates. The optimal temperature on the carbonation reaction was 60 °C achieving an average of 97.4 MPa. The partial pressure also showed a strongly influence on the compressive strength development achieve up to 128.1 MPa under 2.5 bars however, the difference between 1.5 and 2.5 bars was not substantial increasing less than 2 MPa in the compressive strength result.

Pedro S. Humbert, João P. Castro-Gomes
Use of Residues of Crushed Pet Bottles in the Form of a Scale as an Addition to the Manufacture of Concrete

With the increase in the consumption of plastic, human influence has become a problem, since most of these new upstarts are not biodegradable. When there is inefficiency in the activities of recycling or reuse, the effects produced by human activity on the environment are aggravated. The present work proposes a realistic solution in order to avoid that all that plastic that is not recycled or reused correctly reaches the seas and landfills. For the analysis of the results, a completely random factorial design was used. In the design of the experimental program, the determination of the resistance to compression at 7 and 28 days was designed, and the total porosity test at 28 days. The non-destructive tests, ultrasonic pulse speed and electrical resistivity, were conceived at the age of 3; 7; 14 and 28 days. The study showed that the addition of up to 1% of PET during the manufacture of concrete does not influence the quality of the same, in terms of its resistance to compression and porosity.

Joaquín Raúl Cuetara Ricardo
Evaluation of the Aggregates of the Quarry “El Purio” in the Province of Villa Clara

In Cuba the aggregates are the raw material of construction of lower cost, they occupy around 75% of the total volume of the concretes that are produced and the characteristics they present in the future will have a direct repercussion in the performance and obtainment of good quality concretes. This work includes a study of the aggregates that are produced in one of the four quarries in the province of Villa Clara, specifically the gravel, granite and sand that are produced in the quarry “El Purio” in the municipality of Encrucijada. For the characterization of the aggregates, it has realized a group of tests according to NC 251: 2013 [11], and subsequently in the results was proceded in the elaboration of concrete test pipe using cement P-35 and the SikaPlast additive. All this with the purpose of evaluating the real performance that present these aggregates and its repercussion in the obtaining of high resistance concretes. Samples were taken in the storage area and on the conveyor belt, in order to evaluate the technological process and its effect on the final product. This study revealed the influence of the production processes in the studied quarry on the physical and chemical characteristics on fluid concretes of more than 35 MPa.

Daniel Martínez León, María Betania Díaz Garcia
Characterization of Ferrocement Designed with GRP Reinforcement. Deformation and Displacement

Cuba, because it is a Caribbean country, has a very aggressive environment for structures that have reinforcing steel in its structural composition. Engineers have sought new technologies to solve these problems that greatly limit the useful life of the structures projected in alkaline environments. Reinforced concrete is one of the main materials in the construction, however its biggest problem is the corrosion of steel. Nowadays, with the advancement of technology, several studies have been carried out with the use of ferrocement since it is a material that works with small thicknesses, however the use of steel as main reinforcement remains an obstacle to be avoided due to the inevitable danger of corrosion that it has. A new variant has emerged in recent years to reinforce the structures, the use of composite materials of Polymers reinforced with glass fibers (GRP) that is the ideal solution for a tropical island with a highly aggressive environment. In this work, a study of the bending behavior of ferrocement reinforced with GRP meshes using slab-type specimens with different mesh layers will be made, to reach conclusions to be taken into account in the use of this material in the construction sector and in our company (ETECSA) that could sometimes replace reinforced concrete. This could be the structural solution in buildings in aggressive environments, building lighter structures, resistant fronts to the effects of corrosion and much more durable.

Dayana de la Caridad Trelles Barroso


Atmospheric Corrosion Behaviors of Reinforcement Steel in Reinforced Concrete in a Coastal City as Havana, Cuba

Atmospheric corrosion behaviors of reinforcement steel in reinforced concrete in a coastal city as Havana was carried out. Concrete quality was characterized before to expose the reinforced concrete specimens in outdoor exposure condition. An outdoor exposure site at a distance of 10 m from the sea was selected in coastal city of Havana, Cuba. Three reinforced concrete specimens (RCS), one for each water/cement ratio 0.4, 0.5 and 0.6 with concrete covering thicknesses 20 and 40 mm were exposed to outdoor exposure condition. Corrosivity categories of the atmosphere in the outdoor exposure site were Very high (C5) and Extreme (CX). Atmospheric corrosion behaviors of reinforcement steel in reinforced concrete specimens served to obtain service life from the sum of Time-to-corrosion-initiation and Time to corrosion with induced cracking in reinforced concrete structures in a coastal city as Havana, Cuba. Compressive strength and ultrasonic pulse velocity are necessary test but not enough in the concrete quality characterization. Percentage of effective capillary porosity should be determined as a deeper factor for concrete quality characterization. Designs conditions for the concrete elaboration with a quality high and more durable were established, before to carry out the building works in a coastal city as Havana City, as well as in all shoreline north and south of Cuba with the purpose to increase the service life in reinforced concrete structures.

Abel Castañeda, Francisco Corvo, Juan J. Howland, Rigoberto Marrero, Alejandro Fernández
Preliminary Results on Corrosion Rate in Carbonated LC3 Concrete

The new blended cement, LC3, can reduce by up to a 30% of the CO2 emissions per ton of cement, including calcined clay and limestone as main components. However, the low level of clinker content concern about carbonation-induced corrosion of the reinforcing steel. The aim of this project is to measure the corrosion rate and understand the corrosion mechanism of reinforcing steel in concrete made with LC3 cement. The samples were cast in molds specifically designs in order to minimize the carbonation time and the moisture equilibration time. There is a finer porosity for LC3 cement and the porosity decrease when the carbonation takes place due to the transformation of the portlandite into calcite. However, when the clinker substitution is higher, the total porosity increase, but there is a coarsening porosity for blended systems after carbonation because the C-S-H are converted into calcite with a smaller volume. In all LC3 samples, the corrosion rate is higher compared with OPC cement, but there are differences regarding the induced carbonation and natural carbonation especially for LC3 samples with a more tortuous pore system than OPC assuring the high resistance to the carbonation.

Elizabeth Cabrera, Adrián Alujas, Bernhard Elsener, Jose Fernando Martirena-Hernandez
Use of Electrical Test Method on Determination Aging Factor of Concrete Incorporating Supplementary Cementitious Materials

One of the biggest benefits of using supplementary cementitious materials (SCMs) in concrete is the large reduction in the concrete chloride ion diffusion coefficient with age. The formation factor calculated from electrical resistivity measurements is proportional to the concrete effective chloride diffusion coefficient. Traditionally, the aging factor used in service life modeling has been determined from examination of the apparent diffusion coefficient calculated from concrete bulk diffusion experiments, lumping chloride binding and with diffusion. This study proposes to use the formation factor determined from electrical resistivity tests to quantify the concrete aging parameter for service life modeling. To determine the effect of cement chemical composition, four types of cement were tested including type I/II low alkali cement, type IL cement, type V cement and type I/II high alkali cement. Silica fume, slag cement, Class F fly ash, and metakaolin were used as supplementary cementitious materials (SCMs) in binary and ternary blends with different replacement ratios to evaluate the effect of SCMs on the concrete electrical properties with age. The electrical properties were determined at 28, 56, 91, 182 and 365 days. A discussion about the advantages and disadvantages of this method over traditional methods to quantify aging are presented.

Hossein Mosavi, Raid Alrashidi, Mohammed Almarshoud, Mohammed H. Alyami, Kyle A. Riding, Christopher C. Ferraro, Michael D. A. Thomas, Harvey DeFord
Evaluation of Carbonation in Specimens Made with LC3 Low Carbon Cement

The durability is a parameter of great importance to be taken into account in reinforced concrete, this is affected by environmental agents such as CO2, so the present work evaluates the carbonation behavior in hydraulic concrete specimens made with cement Low carbon content (LC3) with respect to Portland cement, located at three exposure sites (Punta Matamoros and University SEDE) with different environmental conditions, by performing the phenolphthalein test according to NC-355: 2004. To understand this phenomenon, other parameters are taken into account such as: the type and content of cement, the pore structure of the material and the curing time. In this way, it can be concluded that concrete made with LC3 and P-35 cement with a characteristic strength of 25 MPa, the former have a better behavior in tidal areas, reaching maximum values of 2.9 mm; This is because those produced with Portland cement have a greater amount of soluble compounds that leach with sea water and affect the pore structure of the same, removing compounds that provide alkalinity to the material. On the other hand, when evaluating the carbonation in places where the relative humidity varies between 50 and 70%, the structural elements produced with the ternary cement present a more unfavorable behavior, due to the percentage of substitution of clinker with the consequent reduction of the alkalinity, Reaching maximum values of 11 mm.

Yosvany Díaz Cárdenas, Ernesto Díaz Caballero, Jose Fernando Martirena-Hernandez
Deterioration of Structures Affected by Concrete Leaching

The present work reflects the results obtained on the study of the concrete leaching in beams and slabs in real structures. Leaching is a phenomenon that promotes the migration of ions from the solution of the pores to the outer side of the structural elements, lowering the pH value of the pore solution and accelerating the corrosion rate of the bars. The objective of this study is to demonstrate how this phenomenon has a remarkable impact on the durability of structures. The investigations were carried out in existing buildings after 5 years of exposure. To evaluate the deterioration rate of the buildings, techniques of polarization resistance, electrical resistivity of concrete and corrosion potentials were applied. Calculation of the remaining section of the reinforced was perform from the direct measurement of the section loss on the steel bars. The research concludes by demonstrating the negative effect of leaching on the durability of the structures.

Alberto Hernández Oroza, Dainelys Guerra Bouza
Atmospheric Corrosion Study of Carbon Steel in Havana Waterfront Zone

Havana City is located along Cuban North-Western shoreline. Many old building structures are located in the waterfront zone to the West of Havana Bay. This zone is defined as “Traditional”. An atmospheric corrosion study of carbon steel CT-3 in the Havana Traditional waterfront zone was carried out. The main aim is to classify the atmospheric corrosivity respecting carbon steel, the main metallic material used in the construction industry. Monthly and cumulative behavior of steel corrosion rate was analyzed, as well as the factors influencing on the kinetics. The influence of climatic factors on chloride and sulfur compounds deposition was also analyzed. Four exposure sites were placed at the same distance from the sea. The results obtained will allow establishing the suitable selection of the primary and secondary protection systems to the structures that are intended to be restored and build in the study area.

Cecilia Valdés, Abel Castañeda, Francisco Corvo, Rigoberto Marrero, Ricardo Montero
Studies Carried Out on Concretes Produced with LC3 According to Cuban Standard NC 120: 2014

In order to implement the low carbon cement (LC3) as part of the Cuban regulations, a study of durability in concretes manufactured with this cement was developed, in different conditions of aggressiveness according to the performance parameters established in the NC 120: 2014 “Hydraulic Hydraulic-Specifications”, the taking of witnesses of the H1, H2, and H4 concretes elaborated in 2016 was carried out. Carbonation depth tests, air permeability, chloride ion migration, were carried out. electrical resistivity, effective to determine the changes experienced by the series 1.5 years versus the series 6 months and the concretes made with cement under carbon LC3 compared to those made with Ordinary Portland Cement (CPO). Subsequent to the analysis of the results, it can be verified that the concretes made with LC3 showed to be in a range of 11–16 times superior in their behavior to the electrical resistivity that those made with Portland cement and 15–22 times more resistant to the chloride ion penetration that those made with CPO, also show a more favorable performance with the passage of time.

Eilys Valdés Alemán, Yosvany Díaz, Jose Fernando Martirena-Hernandez
Monitoring and Interpreting the Early Properties of Alkali-Activated Materials by Electrical Conductivity Measurement

Alkali-activated materials are attracting more and more attention worldwide thanks to their low carbon footprint. Different from the binders based on ordinary Portland cement, the early properties such as flowability, setting, and early strength development, of alkali-activated materials can vary very much and are very sensitive to the compositions of concrete mixture. Conventional methods for testing such early properties are often time-consuming and laborious, whilst the measurement of electrical conductivity is relatively simple and can easily be monitored in an automatic manner. This paper presents a simple monitoring technique based on Winner’s resistivity method and some results measured from mortar samples with various compositions of alkali-activated materials as well as ordinary Portland cements. The preliminary results show some reasonable correlations between monitored conductivity curves and measured/observed early properties. Some interpretations and theoretical considerations to these measured conductivity curves in relation to the early properties and possible chemical reactions are discussed.

Luping Tang, Jun Liu, Emma Zhang
Case Study on Concrete Durability Field Exposure Station in Hangzhou Bay Bridge, China

The Hangzhou Bay Bridge is located at the typical marine corrosion environment. Research on the durability of reinforced concrete acts as an important role to evaluate the service life of the bridge. In order to evaluate the durability of Hangzhou Bay Bridge, the field exposure station of Hangzhou Bay Bridge was built during the construction of Hangzhou Bay Bridge in 2005. Hundreds of concrete specimens were placed at the station for at least 10 years, the chloride ions inside the concrete were tested twice per year. This paper summarized the experience of constructing and maintaining for the field exposure station. Meanwhile, the application of information construction and management of the exposure test station to evaluate the durability of the bridge is introduced.

Weiliang Jin, Jianghong Mao, Jinquan Wang, Dawei Zhang, Weijie Fan
Evaluating Carbonation-Induced Corrosion in High-Volume SCM Mixtures Through the Square Root Model

The dominant cause of premature deterioration and reduced service life of reinforced concrete structures is corrosion. While chloride ingress has typically been the leading cause of corrosion, carbonation-induced corrosion has become an increasingly serious durability concern as higher supplementary cementing material (SCM) replacements have become more commonplace in sustainable concrete mixtures. This study investigated the carbonation resistance for a series of fly ash concrete mixtures placed in an outdoor exposure site to assess the influence of climatic conditions on the propagation of natural carbonation. The carbonation front was determined at 1, 2, and 5 years of exposure for each mixture. In addition, results are compared to similar mixtures placed in an accelerated carbonation chamber at 4% CO2 concentration. The results highlight the efficacy of the square root model to predict the carbonation front and provide an indication of the initiation phase of reinforcement corrosion induced by natural CO2. The carbonation coefficient using the square root model at various ages as well as in accelerated conditions are compared for various mixtures.

Federico Aguayo, Anthony Torres, Omkar Thombare, Thano Drimalas
Diagnose on the State of Deterioration of the Materials of a Ship of the Company of IT Transports of Combustible Transcupet Caibarien

In our country the industrial constructions are very use in different economy sectors, many of them were built in the last century, for that reason is necessary their continuous maintenance and restoration. Some of them present a bad function due of the high grade of deterioration of their structural materials, such is the case of one of the buildings of the fuel transportation company (TRASCUPET) of Caibarién city, in which their main structural elements are in advanced deterioration state, due to: their proximity to the sea, the insufficient protection of their reinforce elements or a high exposition grade of the structural materials to a highly aggressive atmosphere, the absence of maintenance, and for the application of big technological loads due a change in their function. In the work was made: a diagnosis of the physical and mechanical state of the structural elements materials; the geometric model and the structural analysis of the building, the review of the structural capacity of the reinforced concrete elements, and structural steel elements, as well as its unions, taking into a account the concrete deterioration, and the high grade of corrosion of the reinforcement steel and of the structural one. In order to propose solutions to the intervention of the most compromised elements from the point of view of their resistance, and the limitation in terms of work areas and maximum loads to be use in overhead crane.

Santiago V. Sánchez Pérez, Gilberto J. Quevedo Sotolongo, Claudia Rodríguez Rodríguez

Recycled Concrete Aggregate RCA

Prediction of Mechanical Properties of Concrete Made with Recycled Concrete Aggregates Using Statistical Analysis of Data Available in Literature

The concrete design and construction industry has been eagerly adopting sustainability initiatives over the last 20 years to help reduce its carbon footprint, improve economic sustainability, and ensure the important natural resources that support the industry remain available for years to come. Despite these advances, recycled concrete aggregates (RCA) have been significantly underutilized even though they are becoming an increasingly available sustainable resource that can be used to reduce the amount of natural aggregates used in concrete. Use of RCA has been limited, in part, because of a lack of standardized guidance on creating mixture designs and how aggregates may impact concrete properties. Presented in this paper are the results of a statistical analysis of data from over 80 peer reviewed articles that can be used to predict performance in mixtures containing RCA. A large database consisting of 850 compressive strength, 682 elastic modulus, 197 flexural strength, and 462 splitting tensile strength results was created from this literature review with data ranging from 1988 to 2018. Non-linear regression analyses determined that the empirical trends related to compressive strength, elastic modulus, flexural strength, and splitting tensile strength had a linear relationship with the RCA replacement levels depending on absorption capacity, RCA replacement level, effective water-to-cement ratio, maximum aggregate size, and strength of the RCA’s parent concrete. Overall, the RCA replacement ratio and the water-to-cement ratio had significant impacts on concrete mechanical strengths, while other factors such as mix proportioning parameters and aggregate properties had minor effects on the mechanical properties of RCA systems over the large dataset. Additionally, significant reductions in strength were not observed until replacement levels of RCA increased above 20%.

Anuruddha Jayasuriya, Tola Chen, Emily Shibata, Matthew P. Adams
Evaluation of Different Treatment Techniques in Recycled Aggregates for Use in the Production of Concrete

The results of 5 months of research in the topic Concrete produced with 100% recycled aggregates are presented. We worked with a mixed type recycled material from Madrid, Spain and the tests were carried out in the laboratory (OBP) of the University of Applied Sciences of Karlsruhe, Germany. The recycled material was characterized and separated into three fractions for use as aggregates in the production of concretes (i) fine fraction 0–4 mm (ii) intermediate fraction 4–9 mm (iii) coarse fraction of 9–16 mm. To improve the properties of the recycled aggregates, different treatments were used for each of the fractions (i) accelerated carbonation of the fine fraction, (ii) encapsulation of the intermediate fraction with steam curing, (iii) use of MSC, in this case an active mineral addition of calcined clay-limestone base, denominated by its acronym in English LC2. Established as state parameters for accelerated carbonation of the fine fraction Relative Humidity = 75%, CO2 concentration = 20% and residence time of 24 h, which resulted in an increase of 0.7% in the formation of Calcite with respect to the fine fraction without carbonation, the absorption of water decreased by 0.63% and the resistance in mortars after 28 days of curing exceeded by 0.89% the strength of the fraction without carbonation, 28 Mpa and 31, 43 Mpa respectively. For the steam curing of the encapsulated fraction, it was worked under conditions of temperature lower than 60 °C and a residence time of 30 min, obtaining a decrease of 0.75% in the absorption of water with respect to the material without encapsulating. In the concretes produced with the treated aggregates, the best performance series was that which uses a combination of fine carbonated aggregate, encapsulated intermediate aggregate with steam curing and Portland cement 32.5 Mpa.

Giselle B. Limonte Morales, Jose Fernando Martirena-Hernandez, Stefan Linsel
Durability of Recycled Aggregate Concrete Under Real Conditions in Tropical Ambience

The substitution of natural resources by the use of recycled aggregates from construction and demolition waste is a huge advantage for the sustainability in the concrete production. The presented paper considers different processing methods of recycling material evaluated with respect to their advantages and disadvantages in sustainability. But once the recycled aggregates are used in concrete, there is a lag of knowledge in the field of its durability behavior. Durability results from a long-time study on 100% recycled aggregate concretes (RAC) suspended the real conditions in a tropical island are presented with respect to their chloride ingress. As reference a natural aggregate concrete (NAC) with the same w/c-ratio was used. The compressive strength of the RAC reached 30 MPa and is only 6% less than that for natural concrete. Samples of each concrete are exposed to three sites of different aggressiveness depending on the distance to the sea, which involves for one site wet-dry cycles by tides or changes in the relative humidity and the chloride content of the ambience. After 5 month exposure the chloride ingress of samples exposed to the sea shore is up to 39% lower in RAC than in NAC. The changes of chloride ingress with time are observed with a second measurement after 17 month exposure. Results in the carbonation show similar trends in the durability behavior with a lower carbonation depth in RAC. However, remaining tests such as electrical resistance and air permeability show better results for NAC.

Sandra Lichtblau, Stefan Linsel, Jose Fernando Martirena-Hernandez
Potential Use of a Quarry Waste for the Production of Self-compacting Concrete

The main feature of Self-Compacting Concrete (SCC) is its compactability under the action of its own weight, filling formworks and covering reinforcement without the need of applying external energy. Limestone filler is the most used supplementary cementitious materials for the production of SCC in the Buenos Aires Metropolitan Area, Argentina. Alternative sources for fillers can be found in residues from the exploitation of rocks. A good example is the quartzite mud resulting as a residue from the washing of manufactured sand in the Buenos Aires Province. The use of this waste would benefit the environment in reducing the demand for non-renewable natural resources and in adding value to the residue. In this paper, the performance in the fresh and hardened states of SCC made with 25, 50, 75, and 100% of the quartzite residue as a partial substitute of limestone filler is evaluated. Tests include spread, passing time, compressive strength, and capillary water absorption. Results show that the superplasticizer demand increases considerably with the content of the residue. Nevertheless, the properties of concrete in the fresh and hardened states show the feasibility of using the material to produce SCC.

Anahí López, Claudio J. Zega, Gabriela S. Coelho Dos Santos, Leandro E. Carrizo, Juan M. Etcheverry, Yury A. Villagrán Zaccardi
Successively Recycled Concretes Exposed to Sulfate Soil During 11 Years

Recycled concrete is still a material with some questionings about its true durable performance. Studies about recycled concretes exposed to external sulfate attack are very scarce. Generally, accelerated tests focused on the chemical attack are performed. However, studies on conventional concretes point out that structures deterioration by external sulfate attack is mainly due to the physical attack, and not merely by the chemical attack. Then, it is necessary to have results based on real exposure conditions, where transport mechanism and kinetics attack may be very different to that in accelerated test. In this paper, the performance of recycled concretes subjected to four recycling cycles and exposed to sulfate soil during eleven years is evaluated. Concretes were periodically assessed by visual inspection, weight variation and determination of dynamic modulus of elasticity. The results show that recycled concretes presented a satisfactory performance after eleven years of exposure, even better than pattern conventional concrete.

Claudio J. Zega, Alejandro Pittori, Ángel A. Di Maio
Sand Replacement by Fine Recycled Concrete Aggregates as an Approach for Sustainable Cementitious Materials

Waste management and conservation of natural resources are highly discussed topics today. If these subjects are investigated closer, using tools such as Environmental Product Declaration or Live Cycle Assessment, exact numbers considering the CO2 production or amount of produced construction and demolition waste (CDW) can be gained. Despite the existence of those techniques and the promotion of recycling, people are skeptical, or scared, to use recycled building materials. The research focuses on recycled concrete aggregates (F-RCA), which can replace natural aggregates (NA) in concrete production. An urgent need for solutions is approaching fast and many countries, especially islands, lacking capacity in CDW landfill and start to have a shortage of NA resources. Another favourable fact for higher utilization of F-RCA is an approaching lack of sand world-wide. Experimental work is focused on the evaluation of properties of various RCA fraction 0–4 mm, the design of two different series of mixes with replacement ratio 0, 20, 40 and 100% of NA by F-RCA. The rheological properties of fresh mortar and the properties of hardened concrete are examined. Our assumption of higher water absorption and a greater fines content of F-RCA was validated in some cases. Despite this fact, rheological properties of all mixes varied only slightly, and compressive strength differed by 7%. In the second series was recorded significant compressive strength drop of the mix with 100% replacement ratio. Overall it can be concluded that replacement ratio up to 40% has no negative influence on fresh nor hardened properties.

Iveta Nováková, Boy-Arne Buyle
Encapsulation of Recycled Aggregates Using Mixed Construction and Demolition Wastes

Construction and demolition waste (RCD) represents an important contribution to socio-economic development with respect to the depletion of non-renewable resources, where aggregates are approximately 60–75% of the concrete mix and can be reused, therefore the present investigation Its purpose is to study the behavior of hydraulic concretes by encapsulating the intermediate fraction of recycled aggregates. For this purpose, the materials to be used were characterized, being governed, in the case of aggregates, by NC 251 “Aggregates for hydraulic concretes. Requirements.” The fraction of 5–9 mm was encapsulated with the objective that this thin layer covers the pores of the aggregate that cause a high absorption of water, affecting the properties of the concrete. For this we tested with LC3 cement and two proportions of these materials (60 and 40 kg/m3) deciding among them the best mixture for the encapsulation. From this concrete was made, demonstrating that said encapsulation, increases the compressive strength of it.

Isbel Chávez Díaz, Lesday Martínez Fernández
Combining Reactivity Test, Isothermal Calorimetry, and Compressive Strength Measurements to Study Conventional and Alternative Supplementary Cementitious Materials

In this study, we show the results of reactivity testing for a large variety of supplementary cementitious materials (SCMs) and fillers. The reactivity test is performed by measuring the heat release (using isothermal calorimetry) and calcium hydroxide consumption (using thermogravimetric analysis) of SCMs mixed with calcium hydroxide (3:1 ratio of calcium hydroxide and SCM) at 50 °C in a 0.5 M KOH environment. Based on the response in the test, SCMs may be classified into inert, pozzolanic, and latent hydraulic; the pozzolanic and latent hydraulic materials may be further classified into less reactive and more reactive materials. Reactivity test results are compared with isothermal calorimetry and compressive strength measurements on cementitious pastes made with a subset of SCMs. Good correlations are obtained between isothermal calorimetry and compressive strength. Clear correlations between reactivity test results and compressive strength were not seen.

Sivakumar Ramanathan, Prannoy Suraneni, Ying Wang, Hongyou Shan, Amir Hajibabaee, Jason Weiss
Proceedings of the International Conference of Sustainable Production and Use of Cement and Concrete
Prof. Jose Fernando Martirena-Hernandez
Prof. Adrian Alujas-Díaz
Prof. Meylin Amador-Hernandez
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