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Über dieses Buch

This volume contains selects papers presented during the 2nd International Conference on Environmental Geotechnology, Recycled Waste Materials and Sustainable Engineering, held in the University of Illinois at Chicago. It covers the recent innovations, trends, and concerns, practical challenges encountered, and the solutions adopted in waste management and engineering, geotechnical and geoenvironmental engineering, infrastructure engineering, and sustainable engineering. This book will be useful for academics, educators, policy makers and professionals working in the field of civil engineering, chemical engineering, environmental sciences and public policy.

Inhaltsverzeichnis

Frontmatter

Enhancing the Properties of Recycled Aggregate Concrete Using Beneficiation Technique

The concrete industry is a huge industry that is growing at a faster rate and that leads to the consumption of a plenty of Natural Aggregates (NA) which puts the non-renewable natural resources in danger of extinction and the NA resources are remarkably waning day by day. On the other hand, millions of tons of construction and demolition waste residues are generated. Therefore, the use of recycled concrete aggregate obtained from construction and demolition waste in new concrete is a solution for effective waste utilization. Recently, effective uses of Recycled Concrete Aggregate (RCA) in the concrete industry have attracted a lot of attention resource preservations but the use of recycled coarse aggregate directly does not give the safe result in terms of durability properties and compressive strength. So, it has must improved the properties of RCA for replacing it with NA. To enhance the properties of RCA, adhered mortar has to be removed or strengthened. Removing and strengthening the adhered mortar are the two common methods for improving the properties of RCA. The process of removal of adhered mortar is carrying by chemically and mechanically processed. The current study aimed to evaluate the strength and durability properties of concrete at different replacement levels of natural aggregate and recycled coarse aggregate. This study was also intended to enhance the strength and durability properties of concrete by using chemically and mechanically beneficiated recycled aggregate and thus recommend the most appropriate replacement level and the beneficiation method.

Ram Lal Riyar, Kanish Kapoor, Mahesh Patel, S. P. Singh

Early Introduction of STEM Through Sustainable Engineering

To educate the next generation of scientists and engineers, it is important to cultivate critical thinking and problem-solving skills within the context of sustainability. Eva the Engineer, an elective course developed by the University of Wisconsin–Madison engineering students, uses sustainability-focused civil engineering lessons to (1) introduce sustainable engineering practices at the middle school level and (2) encourage young women to pursue science, technology, engineering, and mathematics (STEM). Eva the Engineer students explore the environmental, social, and economic impacts of the infrastructure around them and practice sustainable engineering decision-making with hands-on activities. The primary topics of discussion are infrastructure design, water resources, and waste management. As civil engineering is a central theme of the course, the primary examples of sustainable engineering involve the energy and water reductions using recycled materials in construction applications. For example, students make concrete stepping-stones with recycled materials and calculate energy, water, and greenhouse gas emission savings achieved when recycled materials replace virgin aggregate in concrete. Later, a field trip to a concrete production facility, a landfill, a recycling facility, and a wastewater treatment facility demonstrate the practical implications of construction and waste generation. By the end of the program, students exhibit an understanding of contemporary environmental challenges, basic engineering principles, and the benefits of recycled materials in engineering applications. Program survey results also illustrate a ubiquitous increase in self-confidence in STEM capabilities among students. Engaging the next generation of engineers and scientists in a discussion of present issues is proving to be beneficial for all involved.

Tyler Klink, Morgan Sanger, Renee Olley, Angela Pakes, Tuncer Edil, Sydney Klinzing

Prediction of Moisture Damage in Asphalt Pavements Using a Nanomechanistic Approach

Stripping-related moisture damage in asphalt pavements is a complex phenomenon that deteriorates the durability and performance of the pavements. In recent years, several studies have been conducted at both macro- and micro-levels to find the root causes of the moisture damage. The main goal of this study is to predict the moisture-induced damage using one of the emerging technologies using an Atomic Force Microscopy (AFM) tool. Binder samples originated from two different crude sources have been collected and tested in the laboratory using an advanced mode of nanomechanical mapping, namely the Peak Force Quantitative Nanomechanical Mapping (PFQNM™) mode. In this study, two Performance Grade (PG) base binders and their modified counterparts using polyphosphoric acid (PPA), styrene–butadiene–styrene (SBS), and SBS plus PPA have been evaluated to achieve the goals of this study. To observe the moisture effects, asphalt binder samples were tested under both dry and wet conditions. Test results showed that the surface topography of the asphalt binders and their mechanical properties have had changed notably because of the presence of moisture. It is also evident that the base binders used in this study are highly susceptible to moisture damage, whereas SBS-modified binders have sufficient strength that can be used for the construction of durable pavements. The findings of this study are expected to the State Departments of Transportations (DOTs) and other transportation agencies to gain in-depth knowledge of moisture damage mechanisms in asphalt pavements.

Sumon Roy, Zahid Hossain

Experimental Study of Pervious Concrete and Artificial Clogging

Pervious concrete is a form of lightweight porous concrete, obtained by eliminating or by minimizing the content of fines from the normal concrete mix. The special property of pervious concrete is ‘adequate permeability’ because of its high percentage of porosity (15–40%). However, with the passage of time, pores of pervious concrete get closed or blocked with sediments like sand, clay, or mud, etc. In the present study, to predict the life period in which the pervious concrete works with full efficiency, an artificial method, known as artificial clogging, is performed on pervious concrete to find the critical sediment and effect on the rate of infiltration. An investigation is performed on two mixes (M1 and M2) using sand, clay, and mixture of both as sediment of clog. A total of six cycles were repeated with an increment of 10 g per cycle and the infiltration rate was recorded after each cycle. It was observed that the decrease in infiltration rate was 30%, 50%, and 45% after the sixth cycle where sand, clay, and combination were used, respectively. Furthermore, compressive strength and permeability test were performed on six separate mixes of pervious concrete.

Kanish Kapoor, Mudasir Nazeer, Gowhar Afzal, S. P. Singh

Sustainable Engineering Approaches Used in Electrical Discharge Machining Processes: A Review

Sustainable engineering is the approach in which the process is designed in such a way that there is a balance between the use of energy and resources so that it will not affect the environment and can be conserved for fulfilling the needs of future generations. Sustainable engineering in manufacturing focuses on the enhancement of productivity by controlling process parameters. So, it has become a hot topic in almost every field of manufacturing, aiming to achieve more economical and efficient processes. The key methods of sustainable production mainly include the optimization of energy usage and the innovation of machining techniques, etc. Nowadays, many relevant investigations have been conducted. In this paper, the main study is focused on the sustainable engineering approaches used in the electrical discharge machining processes, various optimization techniques used for better productivity in EDM processes. Effect of different process parameters like pulse-on, pulse-off, peak current, spark gap voltage, tool feed, flushing pressure, electrode polarity, dielectric fluid, etc., in machining operations has been discussed. For better machining time and less energy consumption, the optimization of process parameters, the problem of wire rupture in case of wire electrical discharge machining (WEDM), and the use of different electrode materials in EDM machining operations have been reviewed in this study. Efforts have been made to enhance EDM operations by sustainable engineering approaches with a systematic review of different research articles, industrial catalogs, technical fundamentals, etc. Various conclusions are drawn based on a thorough review of research articles and a list of gaps or future scopes have been provided in this paper.

Ranjit Singh, Ravi Pratap Singh, Rajeev Trehan

Partial Replacement of Cement with Red Mud in Concrete—A Review

Indian aluminium industry generates a significant amount of solid waste such as red mud. Red mud is produced during the refining of alumina by Bayer’s process. It is estimated that for production of 1 tonne of alumina, about 1.0–2.5 tonne of red mud is generated. Annually, more than 4 million tonnes of red mud is produced in India. As red mud contains some toxic elements, dumping of red mud contaminates the soil and water and also covers valuable land. By taking cementitious behaviour of the red mud into account, it can be used in mortar and concrete technology for construction practices by partially replacing cement. The use of red mud with partial replacement of cement proves to be economical because red mud, a by-product of alumina industry is available free of cost. The present study recapitulates the research on utilization of red mud as partial replacement of cement and its effect on mechanical and durability properties in mortar and concrete. Based on data given by different researchers, equations have been formulated for compressive, tensile and flexural strengths of mortar and concrete.

Jaspal Singh, Sanjeev Naval

Parameters Affecting Tufa Precipitation from Recycled Concrete Aggregate

Aggregate generated from concrete is one of the most considered recycled materials used in the U.S. for construction that requires earthwork. However, recycled concrete aggregate (RCA) is known to produce tufa. This study focuses on understanding the composition of the precipitated tufa material from RCA as well as the factors that affect the precipitation process. The precipitation experiments were conducted using PWP (Plummer–Wigley–Parkhurst) reaction vessel using a synthetic metastable RCA solution. Based on the identified parameters, a parametric study was also conducted to evaluate the effectiveness of the suggested mitigation method in the literature to remove and replace fine particles from RCA. Additionally, as part of this parametric study, the effects of contact time and blending with natural virgin aggregate (V.A.) were investigated as alternative mitigation methods. Minteq A2 and geochemical modeling were utilized to calculate the total solid-phase formation under equilibrium conditions from 100% RCA, 100% V.A., and different blends of the two materials. It is shown that the total ionic strength, availability of carbonate and bicarbonate ions, and saturation conditions of Ca and SO4 ions control the mineralogy of the tufa precipitation. Depending on the mechanism, it was found that the calcium carbonate or calcium sulfate minerals can be the dominant forms of precipitation in RCA tufa. Other minor elements contributing to RCA tufa formation were found to be Na, K, Cl, and Si. The parametric study showed that the RCA tufa potential is not dependent on the particle size fractions of RCA but can be reduced by blending RCA with V.A. or decreasing the contact time between water and RCA particle by creating a highly permeable layer of RCA.

Aiyoub Abbaspour, Burak F. Tanyu

Synergistic Effect of Hybrid Carbon Nanomaterials as Reinforcing Phase on the Physico-Mechanical Properties and Pore Structure Refinement of Cementitious Nanocomposites

In the present study, the enhanced physico-mechanical performance of cement mortar nanocomposites by hybrid graphene oxide-functionalized carbon nanotubes over individual nano additives i.e., graphene oxide and FCNTs as reinforcing phases have been investigated. Graphene oxide (GO) was prepared from ball-milled graphite powder (GPb) by in-house designed horizontal ball-mill and carbon nanotubes were functionalized by the acid treatment of the pristine multi-walled CNTs. The surface-treated nanofillers were characterized well by FT-IR, SEM-EDX, XRD, AFM, and Raman spectroscopic techniques. The compressive strength of the HCN-CNCs was improved by 43.02% with respect to control sample at the curing age of 90 days for 0.02% HCNs loadings (by weight percentage of cement). This was found to be superior to the strength enhancements of 27.39% by GO and 17.82% by FCNTs at loadings of 0.02 and 0.08%, respectively. SEM images showed compact hydration products in case of cementitious matrices involving hybrid carbon nanomaterial as reinforcing phase. Better hydration of the various phases has also been confirmed by the XRD studies. In addition to the SEM and XRD, the enhancement in the compressive strength has also been interpreted in terms of porosity. Microstructure of the cement mortars was also investigated by Mercury Intrusion Porosimeter to evaluate the effect of HCNs on the porosity and pore size distribution of large capillary pores (>0.1 µm), medium capillary pores (0.01–0.1 µm), and gel pores (<0.01 µm) of the cement matrix. The improvement in the mortar properties using advanced reinforcement at nanoscale can pave a way to better and sustainable construction based infrastructure.

N. C. Kothiyal, Ramanjit Kaur

Sustainable Solution for the Disposal of Fiber-Reinforced Plastic Waste

Fiber-reinforced plastic (FRP) is one of the gifts to technology that has influenced human life in numerous ways. FRP represents plastic which contains fibers of other materials that add strength, flexibility, durability, and other virtues to the plastic. From the past years, FRP being some composite materials has been used in many industries. But disposal of this FRP waste is becoming a major problem because of increased generation in FRP materials from various industries mainly from windmills. The study deals with use of FRP waste as an additive in concrete, thereby checking the effect of FRP waste on concrete characteristics. Concrete cubes, cylinders, and prisms of M-25 grade concrete were casted with different percentage of FRP waste (0, 1, 2, 3, and 4%) as an additive by the weight of the cement. From the results of compressive strength, flexural strength, and split tensile strength, of the concrete with and without FRP waste, it is observed that the compressive strength, flexural strength, and split tensile strength of the concrete specimens increase when 3% of FRP waste is used as an additive. Hence, 3% of FRP waste can be considered as optimum dosage to be used in concrete.

H. B. Rekha, T. Kiran, N. Jayaramappa, Pooja Tuppad

Geotechnical Behaviour of Copper Slag Mixed with Different Proportions of Soil, Lime, Fly Ash and Cement—A Review

Many countries perceive a rapid growth in the construction industry, which involves the use of natural resources for the development of infrastructure. This development postures a threat to natural resources that are offered. Copper Slag is an industrial waste material and it can be used as the replacement of fine aggregates and cement in the production of concrete. The possibility of substituting natural fine aggregates with industrial by-products such as copper slag offers technical, economic and environmental advantages which are of great importance in the present context of sustainability in the construction sector. The Copper industries units in India leave thousands of tonnes of copper slag as waste every day. These Large quantities of the accumulated copper slag are directly dumped and left on costly land, causing wastage of good cultivable land. Copper slag can be classified as a non-hazardous material by U.S. environmental protection agency regulations based on the solid waste characteristics. Many researchers have studied the physical and chemical properties of copper slag. Researchers have studied the geotechnical behaviour of copper slag mixed with different proportions of soil, lime, fly ash and cement. Studies have been carried out through unconfined compressive strength tests, direct shear tests and CBR tests in addition to basic tests like sieve analysis and consistency limits, etc. In this paper the outcome of previous research studies has been compared, results summarized and gaps in the study have been highlighted with respect to geotechnical applications.

Kuldeep Sharma, Arvind Kumar

A Comparative Study on Using Laterite and Sandstone Aggregates on Mechanical Properties of Concrete

Scarcity of natural aggregates in concrete construction is leading to explore the use of alternative materials, especially various industrial waste products. Mining industry is one such major source of waste materials. Sandstone, which is overlying coal seams, is the largest quantity of waste rock being produced by coal mining industry. Laterite is another waste comes from small scale quarries. An attempt is made to assess the use of laterite-GGBS and sandstone as partial replacement for sand in concrete. Sandstone samples were collected from the dumps of a coal mine in south India and laterite samples were collected from different quarries from the southwestern part of India. Various properties of mine waste samples were determined in the laboratory as per IS codes, the properties were found to be very close to that of natural river sand. Mix proportions were prepared for M20 grade concrete. Mechanical properties of concrete with different mixes (0, 25, 50, 75, and 100% replacement with sand) were determined and compared. As a result, the concrete mixes with the replacement of fine aggregates with 100% sandstone increased in strength properties i.e., compressive, splitting tensile, and flexural strength compared to laterite mixes, where the strength properties decreased with increase in replacement levels. This indicates that sandstone can be an effective replacement for the river sand in concrete.

B. C. Gayana, K. Ram Chandar, Krishna R. Reddy

Strength Properties of Coffee Waste Based Geopolymers

A considerable amount of coffee waste is disposed in the landfills annually. This study aims to investigate the possible use of coffee waste based geopolymers as a green construction material for landfills. Coffee is an organic and a biodegradable material. In order to use coffee waste as a construction material, the strength development of a coffee-based geopolymer was observed. Fly ash or rice husk ash were used as a precursor. These precursors were preferred because they are silica and alumina rich materials. Alkaline activator formed of sodium silicate and sodium hydroxide (Na2SiO3–NaOH) was used to trigger the geopolymerization process. Three variables were tested, the ratio of Na2SiO3–NaOH; effect of ash type, and curing time on the strength development of coffee-based geopolymers. By adding 30% of ash into coffee waste, a geopolymer was synthesized with an activator/ash ratio of 1.7 and Na2SiO3–NaOH ratio of 90–10%, which provided the highest (up to 1000 kPa) unconfined compressive strengths. This paper denotes that the coffee based-geopolymerization products will further develop the organic material into a nondegradable material, therefore suggesting geopolymers as an option to stabilize highly organic soils.

Tugba Eskisar, Selim Altun

Management and Exploitation of Human Hair “Waste” as an Additive to Building Materials: A Review

Recently, biological fibers have become striking topic to researchers, scientists, and engineers as substitute reinforcement, due to their cheap availability, high aspect strength, and appreciable mechanical properties. Human hair fiber (HHF) is one of the unsullied biological fibers. Its accumulation, in the form of waste heaps or in waste stream leads to many environmental problems. All in all, three to four tons of this biological fiber is thrown around like confetti in India annually; posing an environmental challenge. Nowadays, as a commercial application, human hair waste is finding its use in the field of material science. Because of the fact that human hair is strong in tension; it can be used as a fiber reinforcement material. A substantial amount of sulfur is present in human hair because of the presence of “cysteine” amino acid, a major constituent of keratin proteins. Keratin is a primary component of human hair, which is a protein, a polymer of amino acids. Protein “keratin” is incredibly strong, insoluble, and tough. A single strand of HHF can withstand a load of 100–150 gms and on removal of the deforming load, HHF is capable to regain its original position by virtue of its elasticity. This review paper outlines the current scenario of exploitation of HHF as biological composite fiber in various fields of construction. This study shows that HHF is a highly multifaceted material with noteworthy potential in several major areas such as medical applications, cosmetic industry, agriculture, construction material, and pollution control.

Ruhina Anjum, Vaibhav Sharma, Sunil Sharma, Arvind Kumar

Compressive and Flexural Behaviour of Glass Fibre Reinforced Blast Furnace Slag Based Material

For sustainable development, conventional fill material required to be replaced by industrial by-products. In this experimental work, Blast Furnace (BF) slag was used as a base material to develop a new material which could replace the use of conventional fill material in civil engineering works. To achieve the aim the BF slag was blended with cement, glass fibre and water. The mix consists 10% cement by dry weight of BF slag and the optimum water content of BF slag. The mixture of slag-cement was reinforced with glass fibres in four different mix ratios of 0.3, 0.6, 0.9 and 1.2%. For each mixing ratio three different aspect ratios (AR) 385, 769 and 1154 of glass fibre were used. The glass fibre reinforced blast furnace slag based material was then moulded into cylinders and beams. The size of cylinder and beam specimen, used in the experimental study was 75 mm diameter 150 mm long and 50 × 50 × 400 mm respectively. The specimens were then cured for 7, 14 and 28 days curing under room temperature. The effect of mix ratios, aspect ratio and curing periods on density, initial tangent modulus, stress–strain relationship, compressive and flexural strength were studied and results were incorporated in the paper. The relationship between the mix ratio and both compressive, flexural strengths was found to be non-linear. The specimens reinforced with AR 1154 glass fibre yield higher compressive strength at 0.6% mix ratio, and flexural strength at 0.9% mix ratio.

Daipayan Mandal, B. Ram Rathan Lal

Towards Enhancement of Water Sovereignty by Implementing the ‘Constructed Wetland for Reuse’ Technology in Gated Community

The eco-centric wastewater treatment technology entitled ‘CW4Reuse’ (Constructed Wetland for Reuse) for treatment of domestic wastewaters employing horizontal subsurface-flow constructed wetland (CW) beds has been developed and demonstrated in India. A case study of treatment of wastewater using CW is presented in this paper based on our current research and demonstration of the developed technology. The CW4Reuse technology has been demonstrated in the Town of Katel, District of Buldhana, State of Maharashtra, India. The CW4Reuse technology has evidently shown the high treatment efficiency for the wastewater treatment in Katel. It is hoped that the CW4Reuse technology will potentially play a significant role to strengthen the country’s agricultural economy on one hand and will also improve the rural and peri-urban sanitation on the other hand. Additionally, it will enhance the ‘ecosystem restoration and rejuvenation’ of urban as well as rural waterfronts in India. Moreover, the CW4Reuse technology is utilizing the skills of rural people—which will ultimately fortify the inclusive growth of the community.

Rahul S. Sutar, B. Lekshmi, Dilip R. Ranade, Yogen J. Parikh, Shyam R. Asolekar

Removal of Methylene Blue from Aqueous Solution: An Approach of Environmental Friendly Activated Carbon

Methylene blue (MB) dye was adsorbed on an adsorbent prepared from cashew nut shell. A batch adsorption study was carried out with variable adsorbent amount, initial dye concentration and contact time. Studies showed that as the contact time increases relatively there will be an increase in the removal of methylene blue from the aqueous solution. There was also a comparative increase in the removal of dye with the increase in dosage of adsorbent. As the concentration of MB dye increased the percentage of removal of MB from the aqueous solution decreased for a given particular dosage. The results indicate that cashew nut shell activated carbon could be employed as a low-cost alternative to commercial activated carbon in the removal of dyes from wastewater. This work offers an economic incentive to the industrial practice for waste management and eco-friendly approach for removal of toxic dyes from textile waste water.

M. C. Jayaprakash, M. Chaitra, Prarthana Rai, D. Venkat Reddy

An Investigation of Optimal Clay Brick Properties for Evaporative Cooling

The overuse of electricity, which is an indispensable component of our daily lives, is causing the rapid depletion of fossil fuel resources and emission of greenhouse gasses to the atmosphere. It is known that 40% of the electricity consumption of households and industry is due to the use of cooling systems especially during summer conditions. The aim of this study is to develop a natural refrigeration technique that can save a substantial amount of energy. It is hypothesized that with the use of baked clay structures (referred to as ceramic), a natural evaporative cooling technique can be developed, by which the temperature of the surroundings can be dropped by 6 to 10 ℃. This assumption was tested with the help of models. The clay plates with grain sizes 0.700 and 0.250 mm, baked at different temperatures (750, 875, and 1000 ℃) were prepared and tested for vertical/horizontal capillarity and falling head permeability. Afterwards, their evaporative cooling effects were compared. Samples baked at 1000 ℃ and grain size 0.700 mm gave the largest drop in temperature (ΔT ~ 14 ℃ when the air temperatures were between 30 and 40 ℃ and humidity percentages were between 35–40%). Based on these results, 0.700 mm particle-sized clay tiles that were baked at 1000 ℃, which also demonstrated satisfactory levels of capillarity and permeability, were chosen as the structural material for the future prototype tests.

Nida Noorani Ikiz, Mehmet Caputcu

Investigation of Dredged Sediments Reuse as Building Materials

In order to maintain a required water depth and to allow waterways navigable, dredging operations are of a great importance. So, large volumes of sediments are annually dredged in the ports over the world. In Le Havre harbor the annual dredged volume of sediments is close to 1.5 Mm3, which are mainly dumped at sea. Because of its perpetual availability and mineralogical characteristics, the sediment is regarded as a suitable raw material for terracotta production. The aim of this work, assessed in laboratory, is to investigate how dredged and deposited sediments from the Seine estuary and port basins can be used as alternative raw material for the heavy clay industry. The chemical and mineralogical composition of dredged sediments were addressed using X-ray fluorescence (XRF) and X-ray diffraction (XRD), respectively. The physical properties, including plasticity index (PI), organic content, and salinity were investigated. The results from all tested sediments in their raw state showed that their chemical and mineralogical compositions are fairly close. However, their low clay minerals content (6.6%) and their high carbonate content (25.2%) constitute a limitation to their use in ceramic industry. The grain size distribution was appraised on a diagram involving three range sizes (clay, silt, sand), and the results indicated that the raw material falls inside the suitable domain of fired-clay products. Additional ceramic tests performed showed that the raw material can be used as bricks making owing to provided interesting properties, such as firing behavior and mechanical resistance. Leaching test was performed on fired bricks in order to assess the environmental suitability of the construction material. In this framework, The SEDIBRIC project is part of the concern of the “sober management of resources” and aims a sustainable remediation with a low impact on the environment and recovery of dredged sediments.

Ahmed Benamar, Laila Mesrar, Frédérique Bourdin, Sébastien Brasselet

Consolidation Behavior of Compacted Sand–Bentonite–Tire Fiber Mixture for Landfill Application

Compacted sand–bentonite mixtures have been treated as a good substitute for the barrier material at the landfill. At low stress, desiccation-induced moisture variations may cause a reduction in the plastic deformability of bentonite and shrinkage cracking, which can increase the uncontrolled migration of leachates. According to this fact, a series of consolidation and unconfined compression strength (UC) tests were performed on sand–bentonite mixture mixed in a proportion of 30:70 and added with tire fibers in a proportion of 0, 5, 10, and 15%. Results showed that by increasing the tire fiber content the hydraulic conductivity of the mixture increases. For any given fiber content, a higher value of t90 was noticed for the SB30 composite under any range of consolidating pressure. From the shrinkage study, volumetric shrinkage (VS) was reduced as the tire fiber content increased. Surface crack and shrinkage crack developed in the mixture after desiccation and expressed in terms of crack intensity factor (CIF) as well as crack density factor (CDF) both decreased with the inclusion of tire fiber. From UC test, maximum unconfined compressive strength, initial tangent modulus (Ei), secant modulus (Esec), and energy absorption capacity (EAC) of SB30 composite was evaluated and results showed that the improvement of the composite was significant up to 10% tire fiber, thereafter; it starts to reduce sharply with the inclusion of 15% tire fiber.

Krishanu Mukherjee, Anil Kumar Mishra

Feasibility Study for Using Waste Tire Rubber in Bituminous Concrete

An experimental programme was undertaken to investigate the performance of rubber modified bituminous mixes by using rubber as an aggregate, bitumen modifier and filler. The research was carried out in three stages. In the first stage, bitumen was modified by blending it with 5, 10, 15 and 20% (by weight of bitumen) crumb rubber (75–150 µ). In the second stage, fine aggregates in bituminous mixes were replaced with 2.5, 5, 7.5 and 10% rubber aggregates (<4.75 mm) whereas coarse aggregates were replaced with 2, 4 and 6% rubber (by weight of aggregates) of similar size (4.75–13.2 mm) by dry process. In the third stage, the mineral filler was replaced with 2, 5 and 8% crumb rubber (by weight of aggregates) passing 75 µ sieve. Marshall mix design was performed for bituminous concrete at different bitumen contents to evaluate the performance of the bituminous mixes having rubber in different proportions. It was observed that penetration and ductility of modified bitumen decreased whereas the softening point, elastic recovery and viscosity increased with the increase in rubber content. When rubber was introduced into the bituminous concrete mix as a fine aggregate mix performance was comparatively better than the mix having coarse rubber aggregates. However, in both cases, stability values showed a declining trend with the increase in rubber content. The optimum bitumen content increased as the percentage of the rubber increased in the bitumen modified and coarse aggregate mixes. Performance of bitumen modified mixes was found to be better as compared to the mixtures where it was used as an aggregate or as a filler.

Raj Kumar Thakur, S. K. Singh

Applicability Evaluation of Mixtures of Steel Slag Aggregate with Lateritic Soil as Base Material for Road Pavements

Environmental degradation and global warming have become a considerable issue in recent years. The use of more environmentally friendly materials in geotechnical engineering is of preeminent importance. The steel slag aggregate has become an alternative to conventional natural aggregates in road paving works. Therefore, this research aims to evaluate the applicability of the steel slag aggregate as an aggregate for pavement supporting courses (base and subbases). The present research deals with the use of mixtures of steel aggregate and lateritic soil obtained at the site (BR 381/MG) were the subject of the study is located. The experimental program for geotechnical laboratory tests was defined, including the physical and mechanical characterization of the steel slag aggregate, lateritic soil, and three mixtures of these components: 70% steel slag aggregate +30% lateritic soil (M7030), 80% steel slag aggregate +20% lateritic soil (M8020), and 90% steel slag aggregate +10% lateritic soil (M9010). The results of the tests showed that the steel slag aggregate provides satisfactory characteristics to be used as paving material, as long as the expansion of the steel slag aggregate is restrained. The three mixtures of steel slag aggregate and soil, presented satisfactory performance, showing texture compliance, controlled expansion, and high values of California Bearing Ratio (CBR). Therefore, verifying that the steel slag aggregate mixtures can be applied as a base material for road pavements.

Nairo D. T. Buitrago, Victor H. S. Oliveira, Luís F. M. Ribeiro, André L. B. Cavalcante, Fernando F. Monteiro

Waste Plastic Aggregates as a Replacement of Natural Aggregates

The construction industry is the biggest purchaser of natural aggregates which prompted exhaustion of good quality regular sand (fine aggregates). Stream sand, which is one of the constituents utilized as a part of the creation of ordinary concrete, has turned out to be exceptionally costly and furthermore rare. In the setting of such a depressing climate, plastic aggregates can be used beneficially. In this investigation, the reused plastics were utilized to set up the fine aggregates along these lines furnishing an economical alternative to manage the plastic waste. During this study waste Polythene Terephthalate (PET) heated to make PET agglomerate, then cooled and crushed into aggregates that embrace sort of sizes with definite gradation. The different concrete mixes were created with totally different replacement levels (0, 25, 50, 7, and 100 by volume) of natural fine aggregate (NFA) with plastic fine aggregate (PFA). Compressive strength test, Split tensile strength test, Water absorption test, density, workability, and XRD analysis has been performed in this examination. Decreasing in compressive strength was just around 14% and diminishment in water absorption was around 37% for concrete containing 50% plastic.

Bhupesh Kumar Gupta, Kanish Kapoor, Mudasir Nazeer, Mandeep Kaur

Physical and Mechanical Properties Improvement of Miocene Marls (Morocco) Doped by Iron Oxide Fe2O3

The Miocene marls or calcareous clay of the southern Rif groove is one of the geological wealth of the region of Taza in Morocco. This study presents a methodology for recycling the waste iron oxide in ceramics bricks, in a cost-effective and environmentally friendly manner, using the tailings produced from iron mines. Due to its iron oxide content, this waste can be used as a raw material in the manufacture of bricks, at the same time reducing the environmental impact. The study was based on the doping process, which is known to conserve energy, we will see how the addition of these quantities can in some cases lead to profound changes in the properties of the basic solid, both at the macroscopic level and at the level of the microstructural evolution of our materials. Physical and chemical characterization of this marl was carried out before and after doping with iron oxide Fe2O3 following various analytical techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), thermal and ceramics parameters. The doping of the marl was done at different percentages (5, 10, and 15%). The results of the mineralogical analysis of marl after this doping indicate the presence of hematite. Further characterization of the ceramics properties such as linear shrinkage, porosity, and mechanical strength were also investigated by firing doped bricks at a temperature of 900 °C. However, doping with Fe2O3 caused a decrease in porosity and an increase in the mechanical resistance of the bricks. Furthermore, the ceramic tests performed on the product show that the doped marl can be used as bricks due provided interesting properties, such as firing behavior and mechanical resistance. Accordingly, the marl doped with 15% Fe2O3 gives the best improvements in physic mechanical properties.

Laila Mesrar, Ahmed Benamar, Hamza Mesrar, Raouf Jabrane

Fresh and Mechanical Properties of Recycled Steel Fiber Reinforced Self-consolidating Concrete

This paper presents the fresh and mechanical behavior of recycled steel fiber obtained from the end life of scrap tires in self-consolidating concrete. To characterize the fresh and mechanical properties, different fiber volume fractions of 0.5, 1.0, and 1.5% were used. To reduce the cost of concrete, fly ash and silica fume was added which also helps in increasing workability and viscosity, respectively. Fresh properties were characterized by slump flow and J-Ring. Whereas the mechanical properties were investigated in terms of Compressive, split tensile, and flexural strength.

Ashish Simalti, A. P. Singh

Utilization of Waste Lime Sludge and Coal Fly Ash in Construction Industry

Large quantities of industrial by-products are produced every year in India and across the globe. These materials have dual problems of disposal and health hazards. By-products such as coal fly ash and sludge from water treatment plants require greater attention since the magnitude of impact on the environment such as land, surface and ground water resources and air is high, if not properly disposed of. One solution to this crisis lies in recycling waste into useful products in the construction activities to replace the natural materials such as soil and conventional products such as cement wherever possible which will lead to reduction in the economic and environmental problem of waste disposal and also conserve the depleting resources. The aim of this paper is to find the reuse potential of water softening sludge and coal fly ash in the construction industry. In this study, a composite material has been formulated using fly ash and lime sludge with replacing cement to make mortar specimen. The compressive strength of the formulated mix was determined by performing an unconfined compressive strength test. The optimum content of cement, fly ash and sludge was found to be 20%, 40%, 40%, respectively, thereby reducing the cement content to a great extent. It was then observed that the strength of the optimum mix invariably increased 31% by proportionately replacing cement with fly ash and sludge which was dependent on the curing technique used. Oven-dried samples had higher strength than lime water cured samples.

Shristi Khosla Kanoungo, Umesh Sharma, Abhishek Kanoungo

Analysis of Rheological Properties and Moisture Resistance of Nanoclay-Modified Asphalt Binders

The primary aim of this study is to improve the rheological properties and moisture resistance of asphalt binder by the modification of a sustainable material named “nanoclay.” Rheological properties and moisture resistance of selected nanoclay-modified asphalt binders have been evaluated. Three types of nanoclays (Cloisite 10A, Cloisite 11B, and Cloisite 15A) at 1, 2, and 3% by the weight of asphalt binder were blended with a base binder (PG 64-22) from two sources. A blending protocol consisting of a duration of 2 h, a rotation of 2000 rpm, and a temperature of 1500 C were used to blend the nanoclays with the asphalt binders. Rheological properties of nanoclay-modified asphalt binders were then determined by using a Rotational Viscometer (RV) and a Dynamic Shear Rheometer (DSR). The viscosity of the nanoclay 2% Cloisite 10A-modified binder was about 248% of that of the neat binder. It was found that the consistency of a nanoclay-modified binder was significantly higher than the neat binder. The rutting factor (G*/sinδ) also increased significantly for the nanoclay-modified asphalt binders. An Optical Contact Analyzer (OCA) was used to evaluate moisture susceptibility. Binder modified by 3% Cloisite 10A showed the highest surface free energy and cohesiveness. An Atomic Force Microscope (AFM) was used to characterize the nanoclay-modified samples. Surface roughness increased, but no improvement was observed in the DMT (Derjaguin–Muller–Toporov) moduli values. Besides, the adhesion parameter, which indicates the moisture susceptibility, increased significantly.

M. M. Tariq Morshed, Zahid Hossain

A Drainage System for Road Construction on Flat Terrain in New Owerri Nigeria

Conventional road drainage system commonly adopted in the city of New Owerri Nigeria is grossly ineffective and unsustainable, and this gives rise to prolonged pools of water after cessation of rainfall. The water pools often cause road pavement failure, disruption of free flow of traffic, submergence of residential apartments, disruption of commercial activities and exponential rise in mosquito population due to the occurrence of fertile breeding grounds. Research has shown that the use of a trenchless drainage system in road construction, whereby an engineered open trench is backfilled with relatively permeable material, can be a suitable alternative on the flat terrain. It was observed that a 50 cm depth of water completely drains off in such a system within 30 min of cessation of rainfall, instead of the usual two to three weeks duration. Five conditions were examined in the course of the research. The rate of drawdown recorded for the various conditions are 3.7 cm/min for open trench i.e. without a backfill; 3.3 cm/min for trench backfilled with gravelly sand; 2.8 cm/min with fine sand; 2.0 cm/min with mixed sand and 3.5 × 10−4 cm/min for the open concrete drain. It was observed that materials with higher values of both the diameter at 30% passing and coefficient of uniformity are more effective in the drain ability. The unit construction cost of standard concrete drain was found to be about two (2) to three (3) times higher than that of an equivalent sized trenchless drain filled with gravel.

Ozioma C. Owuama, Kennedy C. Owuama

The Effect of Tincal Additive on the Consolidation and Shear Strength Behavior of Sand-Bentonite Mixtures Under High Temperature

The importance of thermal behavior of soils has increased considerably in the last decades. The reason for this, soil properties are temperature-dependent and they are significantly affected by high temperatures and thermal cycles. Previous studies indicate that properties of soils such as shear strength, compressibility, and permeability change at high temperatures. High thermal resistance and durable soils are needed for structures where the soil is exposed to heat such as nuclear waste disposal facilities, buried high voltage cables, energy piles, etc. Boron reduces heat expansion of the glasses, protects the glass against acid and scratches, and also is known with its resistance to high temperature. In this study, the settlement and shear strength properties of sand-bentonite mixtures were determined in the presence of boron mineral; namely tincal under high temperature. The sand-bentonite mixtures were prepared with 10 and 20% bentonite and then 10, 20% tincal were added to these mixtures. The direct shear tests were conducted on all mixtures under 80 °C and room temperature. According to the test results, cohesion value increased in the presence of tincal at room temperature. Furthermore, the internal friction angle values at 80 °C are higher than at room temperature in the presence of tincal. The results have shown that the shear strength of sand-bentonite mixtures increased with tincal additive under high temperature.

Sukran Gizem Alpaydin, Yeliz Yukselen-Aksoy

Effect of Lime Sludge and Fly Ash on Unconfined Compression and Linear Shrinkage Behavior of Kaolinite Clay

The paper investigates the use of lime sludge (LS), fly ash (FA) on unconfined compressive strength, and shrinkage behavior of commercially available kaolinite clay (EPK). The stabilization process was done using lime sludge alone with varying percentages i.e., 2, 4, 6, and 8% by dry weight, as well as a combination with fly ash in varied percentages i.e., 5, 10, 15, and 20% by dry weight. In order to evaluate the strength properties, standard Proctor tests, and unconfined compressive strength (UCS) tests were performed. For estimating the shrinkage, linear shrinkage test was carried out. The UCS samples were prepared based on the optimum moisture content and dry unit weight from standard Proctor tests. The samples were tested after a curing period of 0, 7, and 14 days. In addition, Scanning Electron Microscopy (SEM) tests were performed on UCS samples after shearing. The test results indicated an increase in UCS value with an increase in lime sludge content. Also, the UCS value increased with curing period following a slight decrease. The combination of LS and FA in varied percentages, also had an increase in UCS strength. Also, the UCS value showed an increment in values with the curing period. The reduction in shrinkage behavior of EPK clay was observed with LS and FA. The SEM analysis was conducted to evaluate the reason for strength increase, which was due to the chemical reaction developed between EPK clay, lime sludge, and fly ash.

Sandeep G. Burra, Prabir K. Kolay, Sanjeev Kumar

Influence of Fly ash, Lime, Fines Obtained From Demolished Structures Waste On Geotechnical and Strength Characteristics of Soil

Construction and demolished (C&D) waste which produced continuously during the construction work can be used for this purpose. The disposal of such material has become a big issue because this kind of deposit covers huge landfill area. In present study, the effect of fines obtained from construction and demolished (C&D) waste and fly ash in the soil mixture was evaluated. Fly ash content as 5, 10 and 15%, C&D waste as 6, 10 and 14% and lime as 2, 4 and 6%. The study results reveal that due to the addition of admixtures, Specific gravity, Maximum dry density (MDD) increases and plasticity index (PI) and optimum moisture content (OMC) decreases. On the other hand specific gravity, PI, MDD decreases and OMC increases with the addition of FA and lime. But the effect of fly ash on unconfined compressive strength value of soil at 7 and 14 days are least as compared to the lime and construction and demolished (C&D) waste. The result of split tensile strength (STS) value of soil after treatment with different admixtures at variable percentage and at different curing periods of 7 and 14 days shows that the maximum gain in strength is due to the addition of 6% lime.

Davinder Singh, Tarun Kumar, Amandeep Kaushal

Experimental Study on the Influence of Coir and Calcium Chloride on the Strength Characteristics of Expansive Soil

Expansive soils are the problematic soils, this kind of soil is portrayed by its outrageous hardness while drying and with high swelling process on the wetting. This type of soil has been always presented problems for pavements, light loaded structures, by merging under load and by changing volumetrically alongside regular dampness variety. This article illustrates the influence of inclusion of coir in conjunction with Calcium Chloride on expansive soil stabilization is presented. The present study carried out the viability of using the combination of coir and Calcium Chloride in expansive soils. The effect of coir fibre length 10 mm and three percentages (0.3, 0.6, 0.9% by dry weight of soil), coir pith with three percentages (1, 2, 3% by dry weight of soil) and Calcium Chloride with three dosages (0.25, 0.50, 1.0% by dry weight of soil) were considered. Both untreated and chemically treated fibre reinforced with expansive soil samples were prepared. Maximum dry density, optimum moisture content and UCS tests were conducted. Coir consists of pith along with fibre which was separated to study their independent effects of shear strength behaviour. UCS tests were conducted 0, 7, 14 days of curing, it was observed that the combination of 1% coir pith +0.6% coir fiber +1% CaCl exhibited high shear strength. Mix of coir waste and CaCl2 with expansive soil improved the shear strength behaviour of expansive soils. Expansive soil can be successfully stabilized by the coir and Calcium Chloride.

R. Suresh, V. Murugaiyan

Mitigation of Alkali Induced Heave in Transformed Kaolinitic Clays Using Fly Ash and GGBS

The paper aims to focus on the possibility of using industrial by-products like fly ash (FA) and ground granulated blast furnace slag (GGBS) for stabilizing the induced heave in alkali transformed kaolinitic clays i.e., red earth (ATRE) and kaolin (ATK). Effective usage of industrial by-products such as FA and GGBS for reducing the alkali induced heave in clays can be best solution for reducing the carbon footprint resulting from other stabilizers such as lime. Furthermore, proceeding toward incorporating by-products for stabilization purposes will also reduce the depletion of natural resources. Studies on transformed clays showed unexpected changes in swelling behavior when inundated with water and alkali solution. Samples that exhibited high swelling (i.e., ATRE with 0.1 N, 1 N NaOH, and ATK with 0.1 N NaOH) were selected for carrying out stabilization studies. Decrease in swelling was noticed with the addition of FA and GGBS. Alkali transformed red earth (ATRE) treated with 20% fly ash showed an overall decrease in swelling of about 86% in 0.1 N and 1 N NaOH, whereas 20% GGBS showed a reduction of about 75% in both solution. Furthermore, alkali transformed kaolin (ATK) inundated with 0.1 N NaOH solution showed a reduction in swelling of about 63% and 77% with addition of 10% FA and 10% GGBS, respectively. The reduction in swelling with FA and GGBS is attributed to the formation of sodium and calcium-based mineral polymers, respectively. These polymers bind the partially reacted and unreacted particles restricting the alkali induced swell. XRD and SEM studies highlighted the micro level alterations.

P. Lakshmi Sruthi, P. Hari Prasad Reddy

Using Neural Model for Mimicking the Behavior of Hybrid Foundation

The main goal of Sustainable foundation is in term of cost and less use of natural resources as this field involves intensive consumption of energy and huge amount of natural resources. Hybrid foundations are complex foundation in terms of design and have significance in modern infrastructure development. These are used in situation where structures to support heavy load and the resulting settlement should remain within the acceptable limit. The analysis of this hybrid system of foundation is complex because there are elements such as pile, raft, and soil that affect the resultant settlement. This is because of inevitable interaction between soil and other elements and hybrid foundation. To understand this complex behavior neural models have been constructed to figure out the relative importance of different parameters with reference to load applied under various conditions. These models mimic the experimental setup and predict the resultant settlement in different conditions. The designing of neural models is based on the extent to incorporate experimental set up in their architecture design. The final optimized model predicts the settlements under various conditions and shows the relative effect of changeable (varied) parameters on settlement.

Vikas Kumar, Arvind Kumar

Modeling of Degradation and Failure of Earthen Structural Units

Soil is one of the oldest materials humans have used to build their dwellings and other structures. Almost universally available, easily shaped, highly sustainable, possessing high thermal mass, and easily recyclable, earthen materials are highly sustainable and often a natural choice. Improperly designed, however, earthen structures are subject to erosion, earthquakes, and other types of extreme loading. They may fail in a sudden and brittle manner as well if not properly detailed. We examine the behavior of modern earthen structural elements under shear loading. Cement-stabilized soil block, or compressed earth block, and stabilized rammed earth are used in the number of locations worldwide. In addition to their sustainability, they are cost-effective in many locations. These materials are often stabilized with a small amount of cement for strength and durability. We analyze wall units using a finite element model with embedded strong discontinuities. The bulk material model is a plasticity model that includes both tension and compression caps, a pressure-dependent shear yield surface, differences in triaxial extension and compression strength, isotropic cap hardening, and kinematic shear hardening/softening. The tensile and shear cohesion degradation under large deformation can be modeled. In addition, on detection of localization, an interface may be inserted or activated at the critical orientation. The elements have been extended to include preexisting weak interfaces, such as those between layers of rammed earth, or brick and mortar joints. However, interfaces can also be extended through the bulk material if that path is more critical for a given stress state.

Craig D. Foster

Numerical Studies on Safeguarding of Cantilever Retaining Structures by Sustainable Backfilling Materials

Three-dimensional finite element investigations have been carried out to study the response of retaining structures against lateral earth pressure due to various backfilling materials in order to understand the efficiency of backfilling materials. The behavior of reinforced concrete wall against different backfill soil materials such as sandy soil, clay soil, varying percentage of copper slag along with clay soil and shredded tyre were studied. The elastic behavior of concrete, steel reinforcement bar, sandy soil, clay soil, copper slag, and shredded tyre has been incorporated through elastic model. The behaviors of concrete and backfill material were modeled using suitable material parameters available in literature and identified through detailed literature. The behavior of each element of the wall, i.e., stem, heel, toe, and the shear key against varying sustainable backfill was studied in detail. The lateral displacement, vertical settlement, and stresses developed in each component of the retaining wall were studied and finally the suitable backfill material was identified.

K. Senthil, Ankush Thakur, A. P. Singh

Behavior of Model Strip Footing Resting on Sand Bed Reinforced with 3D Inserts

A series of laboratory model test was conducted on strip footing resting on sand bed reinforced with 2D reinforcement, single sided 3D reinforcement and double sided 3D reinforcement. The various parameters were studied include the depth of variation of 2D and 3D reinforcement and height of variation of vertical members of 3D reinforcement. The experimental study showed a 120% increase in bearing capacity was observed when 2D reinforcement was placed at the optimum depth of 0.5B. In the case of single sided 3D reinforcement, as the height of vertical member of 3D reinforcement was increased, load settlement response and bearing capacity of the soil also increased up to certain limits, further increasing the height beyond that limit drop in the load settlement response is observed. In the case of double sided 3D reinforcement A1 was fixed at 2 cm and height of A2 was varied from 1 to 3 cm. An increase in the bearing capacity was observed more than 300% in the case of single sided 3D reinforcement and more than 350% in the case of double sided 3D reinforcement. Double sided 3D reinforcement can provide additional confinement and passive resistance to the soil, as compared to 2D and single sided 3D reinforcement for the same area.

Prince Karandeep Singh, Arvind Kumar

Environmental Impact Assessment of Soil Stabilization Materials

During the past few decades lot of emphasis has been laid upon utilization of waste materials to improve the sustainability in environment. Even though we have been able to successfully utilize the primary waste product but its environmental impact remains the cause of concern. Without determining the toxicity characteristics of compounds formed during the reactions and their potential hazardous characteristics we cannot claim that the added compound has proven to be environment friendly on mere eradication of primary pollutants or waste products. The study has been carried out to determine the formation of compounds on addition of Fly Ash (FA) in soil. X-ray diffraction technique was incorporated in the study to characterize the compounds formed during the analysis. During the course of investigation calcium, aluminum and sulfur-containing compounds were observed. In addition to compounds, a variety of mono-valent, Di-valent ions were also traced. The ecological toxicity level of compounds was determined and compared with the toxicity potential of primary additive compounds.

Ilyas Bhat, S. Rupali, Arvind Kumar

The Role of Environmental Geotechnics in Building Earth Dike Made from Side Energy Products

Brownfields are nowadays frequently being used for storing side energy products from the rear fuel cycle at classic power plants. These products are deposited in liquid form by pipeline need a certain space bounded by an earth dike. The use of traditional soil in the dike can be costly and therefore the construction of dikes from local material—coal slag—is proposed. The earth dike was built on the sediments in former sludge lagoon. Shortly after the first flooding of slag there was a breach of the dike. Geotechnical solution followed the incident: field tests were carried out and laboratory analyzes were performed. Mathematical analysis based on the results from field and laboratory tests was simulated. The numerical calculations were used to determine the most probable causes of the breach and the proposed solution—redevelopment of the dike.

Petr Cernoch, Jiri Kostal

Enhancement in Shear Strength Characteristics of Soft Soil by Using Nanomaterials

Soil being particulate system, encompasses a wide variety of particles, which has made it one of the most complicated natural materials to be modeled. Among soils, soft soil deposits pose challenging problems to geotechnical engineers for the assessment of reliable behavior of these soils to be used either as a foundation medium or construction material. For chemical stabilization of soils, there are numerous chemical additives such as polymers, cement, and other compounds available for treatment of soft soils, however, nanomaterials, including Nano-Alumina and Nano-Silica have attracted great interest among researchers. Unlike other traditional and non-traditional additives, nano additives are used directly with the soil or being an additive for the stabilization of marginal soil deposits. In this study, nanometric additives have been chosen to investigate their influence on strength behavior of clayey soil. Soil samples from three locations were collected and characterized in the laboratory. Also, SEM and XRD tests were carried out to identify the underlying mechanisms of Nanomaterials. Based on basic geotechnical investigations, the soil samples from two locations were selected for treatment using Nanometric additives of Al2O3 and SiO2 at varying percentages of 0.5, 1.0, 1.5, and 2.0%. The test results revealed that the unconfined compressive strength increased significantly with increasing Nano additives. The addition of these nanoparticles increases sample’s reactivity even at an early age and subsequently, compressive strength is increased. Therefore, the main goal of this study was to stabilize soft soil deposits for its bulk utilization in various geotechnical applications for sustainable environment.

B. A. Mir, S. Hariprasad Reddy

Building Derived Materials—Sand Mixture as a Backfill Material

The growing interest in utilizing waste materials in civil engineering applications has opened up the possibility of constructing reinforced soil structures with unconventional backfills. According to World Bank reports (2012), generation of Construction and Demolition Waste (CDW) will reach 5 billion tons by 2025 globally, out of which major generators are Asia-pacific and North America regions. Improper handling and disposal of this inert waste create environmental hazards and also occupy land space. Recycling and reuse of CDW may help to attain a sustainable ecosystem. CDW comprises wood, concrete, and brick, glass, tiles, out of which concrete and brick forms a major part and is termed as Building Derived Materials (BDM). A series of triaxial tests are conducted to investigate the stress–strain relationship and strength of BDM and a mixture of sand and BDM. The laboratory test results are used to establish the parameters required for the hyperbolic modeling of these materials. Hyperbolic parameters are varying with an increase in confining pressures and with percentage addition of BDM. Plastic properties of sand–BDM are computed with this model and well matching with experimental data. The analysis indicates that the performance of sand–BDM mixture, being both lightweight and reasonably strong, compared well with that of sandy gravel, as a backfill material.

M. Jayatheja, Anasua Guharay, Arkamitra Kar, Ashok Kumar Suluguru

Erosion–Filtration Analysis for Assessing Hydraulic Instability of Dams in Morocco and Global Warming Effect

The climate change including very long dry seasons can threaten vulnerability of dams and dikes by reducing their resistance to internal erosion. It is, therefore, questionable how long degradation of soil properties can affect the operating life of hydraulic structures. This research is devoted to investigate the susceptibility to internal erosion of many earth dams in Morocco. For this purpose, many erosion–filtration tests have been conducted on samples collected from core soil or downstream filter of three dams (embankment dam and zoned earth dams). Materials have been analyzed with respect to the particle size distribution, plasticity index, permeability, and their suitability for dam construction. This has been deduced from usual engineering guidelines. The investigation involves combined Hole Erosion–Filtration experiments for modeling internal erosion of a base soil and the filtration through a downward granular filter. The results of experimental hole erosion tests conducted on base soils show a high resistance of the soils against erosion, and a linear enlargement of the hole was recorded. Moreover, usual guidelines indicate a slow to extremely slow erosion of tested core soils and classified as being highly resistant to erosion. The results from combined erosion–filtration tests provide a method on quantitative measurement of the filtration efficiency and particle size selection. Experiments involving previously dried core soils reveal that the desiccation step makes the soil more susceptible to erosion, indicating that drought phase may affect strongly the core resistance against erosion in dams.

Ahmed Jalil, Ahmed Benamar, Mohamed Ebn Touhami

Rainfall Thresholds Triggering Landslides: A Review

In different physiographic and climatic regions worldwide, rainfall is recognized as one of the most common triggering factor for landslides causing severe damage to property and lives of large number of people every year. Urbanization in case of hilly areas has led to the need of detailed study and research in the field of landslides triggered by rainfall. Rainfall thresholds are statistical approximation of minimum rainfall conditions that trigger landslides for a particular mix of geologic, hydrologic, and topographic variables in a particular area. In the hazard-prone areas, the assessment of landslide-triggering rainfall thresholds is useful for development of early warning system. A lot many studies are available on this topic, which determine and estimate the amount of rainfall causing landslides. This paper aims at presenting a current state-of-the-art on the application of rainfall thresholds concepts, techniques, and methods for landslide occurrence with a focus on recent papers (after 2000) published in peer-reviewed journals.

Kanwarpreet Singh, Virender Kumar
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