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2024 | Buch

The Basics of Aggregates

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Über dieses Buch

Aggregates are among the most common natural resource used in everyday's life, having enhanced life quality. They are essential for construction, being utilized in nearly all residential, commercial, and industrial building construction and most public work projects such as roads, highways and bridges, railroad beds, dams, airports, tunnels, and many others. In the future, the rebuilding of deteriorated roads, highways, bridges, airports, seaports, and private and public buildings will require vast amounts of aggregate. Although it is almost impracticable to know the total amount of aggregates extracted every year globally, it is roughly estimated that annual aggregate production totals about 25 billion tons. Both developed and developing nations require extensive use of aggregates.
The book "The Basics of Aggregates" covers all topics related to utilizing this type of material, including the properties of aggregates, types of deposits, geological occurrence, exploration methodologies and extraction methods, and processing techniques as well as their main applications and the importance of recycled aggregates. It serves as a basic text on aggregates for natural sciences and provides information about the main aggregate materials comprehensively with extensive number of illustrations and equips students to handle the mining cycle of aggregates. It enhances the understanding of the different aggregate types, being interdisciplinary and practice-oriented.
This textbook addresses bachelor and master students of geology and general earth science as well as students of engineering and environmental sciences. It is written for undergraduate and graduate students, researches and professionals alike.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
This chapter introduces the reader to the world of aggregates. Data on the worldwide consumption of aggregates are discussed as well as their main types and sources, including recycled aggregates. Aggregate applications are described and the mining cycle of aggregate production is briefly introduced. The importance of the influence of aggregate production in the circular economy is further discussed, including sustainability, and the criticality of aggregate resources is highlighted. Finally, illegal extraction of aggregates is cited as one of the most important environmental concerns of aggregate production.
Manuel Bustillo Revuelta
Chapter 2. Properties and Testing
Abstract
This chapter discusses the basic properties of aggregates and the associated test standards. Aggregate properties are defined, and the significance of each property is briefly discussed. At the same time, commonly used tests for determining the properties of aggregates are described. General properties of aggregates mainly include the petrographic description of the aggregate, which provides valuable information about the mineralogy, chemical composition, grain size, and texture of the aggregate particles. Geometrical properties are those related to particle size distribution (gradation), shape (i.e., roundness) and surface texture (i.e., broken surfaces) as well as the content and quality of the fines. All these properties are key features that control the utilization of aggregates in many end-uses. The mechanical and physical properties of aggregates include physical properties such as density, water absorption, and porosity as well as mechanical properties such as resistance to abrasion and resistance to polishing. The importance of the thermal (thermal volume change, thermal conductivity and integrity during heating) and weathering (freezing and thawing and wetting and drying) properties of aggregates depends on their end-use, with some of the properties (i.e., thermal properties) being rarely needed. Chemical properties are very important in applications such as concrete or asphalt because some types of aggregate contain minerals that are chemically reactive and can affect the final behavior of the mixture.
Manuel Bustillo Revuelta
Chapter 3. Geological Occurrence
Abstract
This chapter introduces the geological characteristics of aggregate deposits. This type of mineral resource, regardless of whether they are rocks for crushing or sand and gravel for direct utilization, is present in numerous geological environments, all with their own unique characteristics. Sand and gravel deposits are formed by the erosion, transportation, and deposition of fragments. They are most common in glaciated areas, alluvial basins, and fluvial deposits near rivers and streams. Sand and gravel deposits are principally Pleistocene or younger and are a reflection of the region’s latest geological and climatic history. In fluvial deposits, aggregates are commonly mined directly from the river channel and/or from river terrace deposits. Glaciated regions also contain numerous deposits of this type. Marine deposits on continental shelves are large potential sources of sand and gravel, being generally sand-size and finer. Many different types of rocks are suitable for utilization as aggregates when crushed but high-quality aggregates are exclusively obtained from very hard, dense siliceous rocks. Limestone, dolostone, and sandstone are the most widely used sedimentary rocks as aggregate. Granite, basalt and andesite are typical examples of igneous rocks commonly utilized as aggregate whereas gneiss, marble, and quartzite are metamorphic rocks quarried for aggregates.
Manuel Bustillo Revuelta
Chapter 4. Exploration and Evaluation of Deposits
Abstract
This chapter is concerned with the process of analyzing an area to find aggregate deposits as well as their resource/reserve evaluation. The information collected during exploration is utilized for assessing the size and quality of the aggregate deposit and for determining if there is the potential for it to be extracted. Two principal stages are outlined in aggregate exploration: reconnaissance exploration and detailed exploration. The main methods applied at different phases are discussed, especially geophysical methods because they are essential in the exploration of a sand and gravel deposit. The methods discussed are organized in order of scale and stage, from photogeology to drilling, through remote sensing and geophysical surveys. Technical and economic/financial methods used for evaluating an aggregate mining project are considered. The technical aspects are related to the geological setting of the deposit and the main characteristics of the material (i.e., tonnage). For this, a general introduction to geostatistics from a conceptual point of view and the principal classical methods utilized in the evaluation process are provided. The economic/financial methods cover the estimation of the principal economic inputs and outputs in the project and the amount, type, and cost of capital forthcoming for a project. Net present value, internal rate of return, payback period values, and risk analysis permits are briefly explained.
Manuel Bustillo Revuelta
Chapter 5. Extraction Methods
Abstract
This chapter reviews the main topics related to aggregate extraction from surface and underground methods. Although aggregate sources can be widely variable, the methods of extraction are very similar throughout the world, with crushed rocks mainly extracted from quarries (surface and underground mining) and sand and gravel from gravel pits. In the latter, the aggregate can be extracted above or below the waterline. These extraction methods are fairly well described together with loading and hauling equipment. Working hard rock quarries is a more complicated and intensive process than quarrying sand and gravel. Drilling and blasting in hard rock quarries are also briefly explained in this chapter because they are often necessary to extract the required rock. To illustrate the development of each mining method, several case studies are included in the text. The last heading of the chapter is devoted to marine aggregate extraction.
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Chapter 6. Processing Techniques
Abstract
Processing techniques basically involve crushing and screening in crushed stone aggregates while sand and gravel materials are processed using screening and washing methods. These processes occur in an aggregate processing plant, whose objective is to prepare the materials in an adequate form for their final utilization as aggregates. Both types of aggregates finally need stockpiling and load out for transport. Upon sale, the final product is loaded on trucks, trains, or barges for transport to the market. Sand and gravel processing for most applications is first accomplished through washing to extract clayey components. Sand fraction separation, grading of the gravel into several, sand classification, and dewatering are the following processes until the final product is obtained. For crushed rock aggregates, after blasting in the quarry, trucks or conveyors move material to the processing plant where crushing (most operations use jaw and gyratory type crushers for primary crushing whereas secondary crushers are usually cone crushers or horizontal-shaft impact crushers) and screening are the main processes for producing fractions with the needed requirements. The processing methods require efficiency since the additional cost is added to the final product each time the aggregate is handled and/or processed.
Manuel Bustillo Revuelta
Chapter 7. Environment and Sustainability
Abstract
This chapter draws attention to all topics related to the environment and sustainable development in the aggregate mining world. It provides a general overview of the environmental issues associated with the design, development, operation, and closure of aggregate operations. The description starts with some comments about mining, the environment, and sustainability, including the definition of sustainable development and the importance of an environmental management system using ISO 14001 standard. The most important potential environmental impacts and their management are discussed: air emission of particulate matter, increased noise levels, vibrations associated with blasting, water affection, biodiversity loss, and visually (negative visual aesthetic) disturbed landscapes.
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Chapter 8. Applications
Abstract
The aim of this chapter is to review the main applications of aggregates in construction. Aggregates can be used as a construction material in two large types of applications: unbound applications (the aggregate is not bound) and bound applications (mixes containing binding agents such as cement or bitumen). The largest proportion of aggregates is used to manufacture concrete, which is the most widely used building material in the construction industry. Aggregates constitute, in percentages greater than 90%, most of the layers of road surfaces. They are the principal material in pavement construction. One of the most demanding applications for crushed aggregate is railway ballast. Armourstone consists of coarse aggregates utilized in hydraulic structures and other engineering works. Gabion is a robust structure comprizing a double-twist wire-mesh basket filled with hard, durable stone. It performs a great variety of functions within coastal, estuarial, and fluvial environments. Drainage and filter aggregates are sand, gravel, or crushed stone or mixtures thereof. They play essential roles in many engineering projects. Finally, decorative/ornamental aggregates can be used in a wide variety of spaces such as commercial and residential spaces, domestic pathways, driveways, car parks, architectural landscaping, gardening (patios and rockeries), sports grounds, etc.
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Chapter 9. Recycled Aggregates
Abstract
This chapter introduces the reader to the basic characteristics of construction and demolition waste (CDW) as well as recycled aggregate, which is one of the most important products obtained from construction and demolition waste. Composition of CDW, including its most interesting component (concrete), as well its management is discussed. Valorization plants (stationary and mobile) for the treatment of construction and demolition waste are explained. Recycled aggregates, reprocessed materials previously used in construction, are further discussed and their main properties commented. Finally, the applications of recycled aggregates are briefly commented: production of concrete and pavements as well as general fill and embankment material, and for erosion control.
Manuel Bustillo Revuelta
Metadaten
Titel
The Basics of Aggregates
verfasst von
Manuel Bustillo Revuelta
Copyright-Jahr
2024
Electronic ISBN
978-3-031-42961-3
Print ISBN
978-3-031-42960-6
DOI
https://doi.org/10.1007/978-3-031-42961-3