The characteristic of recycled aggregates could be different by its parent concrete because the parent concrete was designed for its purposes such as permeable, durable and high strength concrete recycling of concrete is a relatively simple process. Properties of concrete every civil engineer must know. Standard specification for lightweight aggregate for insulating concrete. So understanding properties and function of aggregates plays an important role in determining the strength of concrete.
These different properties of aggregate allow designers and contractors the most flexibility to meet their design and construction requirements. Properties of pervious concrete incorporating recycled. What is concrete and what are the properties of concrete. In the precast concrete industry, recycling of discarded or rejected precast concrete products as rca in new precast. This paper brings together the findings and opinions found in the literature, published principally during the past 40 years, concerning the effects of aggregate size, shape, and surface texture on the properties of bituminous mixtures. Mixes with 10%, 30%, 50% and 100% by volume replacement of fine natural aggregates fna with fra were produced and tested for water. Effect of recycled concrete aggregates on strength and. Approximately 75% of the volume of concrete is occupied by aggregates, so quality of aggregates plays an important role in determining properties of concrete. Aci 2r03 guide for structural lightweight aggregate concrete and astm 169 d lightweight concrete and aggregates both are excellent references.
Properties of concrete with recycled concrete aggregate. This paper deals with analysis of properties of concrete replaced by recycled construction and demolition debris as aggregates in concrete mix. Physical properties of aggregates 54 aggregate tests consensus properties required source properties optional aggregate criteria based on aggregate blend based on traffic and depth into pavement design aggregate structure 0. Properties of concrete concrete is an artificial conglomerate stone made essentially of portland cement, water, and aggregates. Sep 30, 20 concrete is a highly versatile construction material, well suited for many agricultural applications.
This bulletin describes types of aggregates normally used in concrete. At the earlier stage of concrete development, it was. Stutzman materials and structural systems division engineering laboratory. Tr 11 properties of new zealand concrete aggregates. Aggregates are used in concrete to provide economy in the cost of concrete.
Consequently, selection of aggregates is an important process. Concrete aggregates function, properties, characteristics. The chemical interaction between cement and water binds the aggregate into a solid mass. Abstract aggregates play a major role in determining the fresh and hardened properties of concrete. Influence of aggregate characteristics on concrete. Aggregates consisting of materials that can react with alkalies in cement and cause. Although some variation in aggregate properties is expected, characteristics that are considered include.
Mechanical properties of recycled aggregates concrete. Sand, gravel and crushed stone are the primary aggregates used. The strength of aggregates do not contribute to the strength of concrete for low strength concrete. Aggregates are the most mined materials in the world. Naturally occurring concrete aggregates are a mixture of rocks and minerals see table 51. Gradation of aggregates and its effects on properties of.
Recycled aggregate an overview sciencedirect topics. Aggregate properties significantly affect the workability of plastic concrete and also the durability, strength, thermal properties, and density of hardened concrete. Determining the replacement ratio of this debris as fine and coarse aggregate is presented in this paper. Natural aggregates were replaced by rca at levels of 0, 10, 20, 40, 70, and 100%. They give body to concrete, reduce shrinkage and affect economy. Concrete made with hunua aggregates had reasonably good hardened properties with elastic modulus values in excess of 30 gpa and drying shrinkage of less than 850 microstrain at 56 days. Influence of aggregate characteristics on concrete performance. If grading of aggregate is varied, it also changes cement paste content cost economy, workability of the mix, density and porosity. Concrete is a mixture of cementitious material, aggregate and water. The properties of the recycled aggregate and of the new concrete made from it, with nearly 100% of aggregate replacement, were tested. Pdf aggregate are the important constituent in concrete.
Desirable properties of aggregates selection of an aggregate material for use in an asphalt concrete pavement depends on the. Pdf gradation of aggregates and its effects on properties of. Slag was also incorporated to enhance the performance and sustainability of the concrete mixtures. There has not been much research on the effects of coarse aggregate content. Aggregates and their properties in concrete concrete society of. The characteristics of aggregates impact performance of fresh and hardened. Properties of concrete with coconut shells as aggregate. Aggregates strongly influence concretes freshly mixed and hardened properties, mixture proportions, and economy. To determine the effects of clay content on the strength, shrinkage, and durability of concrete. The important characteristics of aggregates for concrete are listed in table 52 and. Pdf properties of pervious concrete with various types. Close to half of the coarse aggregates used in portland cement concrete in north america are gravels.
The effective porosity of concrete was within the normal range around %. But there are properties or characteristics of aggregate which influence the properties of resulting concrete mix. Aggregates generally occupy 65 80% of a concretes volume. Aggregates aggregates commonly considered as inert filler material which occupy 60 to 80 percent of the volume of concrete70 to 85 percent of the weight of concrete. Specific gravity absorption sand fineness modulus asr aggregate class use in bridge superstructure use in paving. Strength, durability, and many other factors depend on the relative amounts and properties of the individual components. While the fine natural aggregates utilized in concrete production usually present a content of fine materials less than 1%, the fine recycled aggregates have contents varying from 6% to 11%, depending on the original waste and the crushing process utilized. Concrete basics a guide to concrete practice contents foreword page 2 chapter 1 concrete materials pages 35. Properties of pervious concrete with various types and sizes of aggregate article pdf available in matec web of conferences 276. Effects of aggregate properties on concrete like grading of aggregates depends on the proportions of coarse and fine aggregate. Fresh concrete will be plastic so that it can be moulded to any desired shape.
Various studies have been conducted on different types of natural coarse aggregate to. The lowest values of the compressive strength were achieved only when the crushed 216 mm. Some are produced and processed specifically for use as aggregates. Concrete containing metallurgical sludge waste is of higher compressive strength after 7 and 28 days, with up to 60% of waste as a sand. Coarse aggregates have properties such as size, shape, moisture contents, specific gravity, density etc. Aggregates are a component of composite materials such as concrete and asphalt concrete. Apr 08, 2018 properties of concrete during its plastic stage. Properties of concrete while cement in one form or another has been around for centuries, the type we use was invented in 1824 in britain. Appendix 3h pages 3437, 153155, extracted from the. Naturally occurring concrete aggregates are a mixture of rocks and minerals see. Absorption, porosity, and permeability the internal pore characteristics are very important properties of aggregates.
Crushed concrete aggregates properties and uses of recycled. Crushed concrete aggregates properties and uses of. Importantly, the water absorption and deleterious material content of rca can be measured and used to prequalify the material for use in structural concrete. Standard specification for lightweight aggregates for structural concrete, c 331. Aggregates aggregates generally occupy 65 80% of a concrete s volume. In this paper, the permeability properties of fine recycled aggregate concrete are presented. The characteristics of aggregates impact performance of fresh and hardened concrete. Aggregates aggregates commonly considered as inert filler material which occupy 60 to 80 percent of the volume of concrete 70 to 85 percent of the weight of concrete.
Aggregates are inert fillers floating in the cement paste matrix for concretes of low strength. Coarse aggregate was then replaced with cs in 10 m2, 15 m3, 20 m4 percentages to study effect of cs replacement. Standard specification for lightweight aggregates for concrete masonry units, and c 332. It was named portland cement because it looked like the. The fra used come from demolished concrete of known properties. Introduction strength of aggregate particle shape and texture grading moisture content classification of aggregate. Aggregates strongly influence concrete s freshly mixed and hardened properties, mixture proportions, and economy. Effects of aggregate properties on concrete size, grading.
The size, the number, and the continuity of the pores through an aggregate. The effect of concrete composition and aggregates properties on performance of concrete 318 the crushed 0. It is an important factor and has a maximum influence on workability. Aggregates are chemically inert, solid bodies held together by the cement. In general, there is a 10% decrease in strength when recycled coarse aggregates are used. However, thermal properties of concrete are influenced by the concretes mixing proportions, aggregates thermo physical properties that it. Aggregate particles have certain physical and chemical properties which make the aggregate acceptable or unacceptable for specific uses and conditions. The properties of pervious concrete made with recycled concrete aggregates rca were investigated. Stutzman materials and structural systems division engineering laboratory jussara tanesi mengesha beyene haejin kim jose munoz ses group and associates ahmad ardani federal highway administration. These effect of aggregate properties on concrete are discussed in detail. The uses of crushed concrete is divided into two major groups.
See chapter 2 concrete properties cement the cement powder, when mixed with water, forms a paste. Construction aggregate, or simply aggregate, is a broad category of coarse to mediumgrained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Although aggregates are most commonly known to be inert filler in concrete, the different properties of aggregate have a large impact on the strength, durability, workability, and economy of concrete. The effect of shape, texture and grading of aggregates on fresh concrete was evaluated experimentally, quantified by means a proportioning method based on packing density concepts, the compressible packing model cpm, and analyzed by an empirical tool suggested by shilstone. Thermophysical properties of masonry and its constituents, r. Pdf influence of crushed coarse aggregates on properties of. Effect of recycled aggregates on mechanical properties of. Crushed concrete has a wide variety of uses within the civil construction industry and has been incorporated into major projects. Physical properties of structural lightweight concrete the information present in chapter 6 and 7 is also covered in a more general way in. The fresh concrete should possess following properties. Blast furnace slag is an example of a synthetic aggregate. Influence of aggregate characteristics on concrete performance dale p. Mix proportions in order to investigate properties of cs concretes, six mixes were employed.
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