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Crushed aggregate with the proper proportions provides a better bond with the cement matrix and adequate workability. Admixtures: Many types of admixtures alter the workability of fresh concrete, either by design or as a side-effect. Surfactants such as superplasticizers reduce attraction between cement and aggregate particles, allowing mixes ...
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Fig. 4 depicts that substitution of crushed cockle shell content as partial fine aggregate influences the concrete workability. Increasing the proportion of crushed cockle shell used, resulted in the drop of slump value. The mixture without the addition of cockle shell is more workable compared to the mixtures with crushed cockle shell.
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Crushed stone is produced by crushing quarry rock, boul-ders, cobbles, or large-size gravel. Crushed air-cooled blast-furnace slag is also used as fine or coarse aggregate. The aggregates are usually washed and graded at the pit or plant. Some variation in the type, quality, cleanli-ness, grading, moisture content, and other properties is expected.
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The test program identified aggregate properties, mix design properties, basic mechanistic properties, workability, and moisture susceptibility of the applied mixtures containing crushed concrete materials. Although the use of crushed concrete materials generally resulted in increased water demand and
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Among these, aggregates, i.e. inert granular materials such as sand, crushed stone or gravel form the major part. Traditionally aggregates have been readily available at economic prices and of qualities to suit all purposes. However, in recent years the ... Workability by slump cone was determined by using IS: 1199-1959[25] for RA concrete ...
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The potential for the recycling and reuse of CDW is high. There is a huge market interest to reuse and recycle aggregates derived from CDW in construction materials and projects [6,7,8,9,10,11,12,13,14,15,16,17].Over the last decades, many studies have been performed to evaluate the feasibility of using CDW in projects, such as:
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aggregate. Not only that, being round in shape, the frictional resistance is also greatly reduced. This explains the reason why river sand and gravel provide greater workability to concrete than crushed sand and aggregate.
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Workability. Aggregates influence the workability of the concrete by the amount of aggregate, the relative proportions of fine and coarse aggregate, and the different aggregate properties. ... concrete needs two to three percent more sand by absolute volume and 6 to 9 kilograms more water per cubic meter when crushed sand is used instead of ...
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material such as sand, gravel, crushed stone, blast-furnace slag, and lightweight aggregates that usually occupies approxi-mately 60 to 75% of the volume of concrete. Aggregate properties significantly affect the workability of plastic concrete and also the durability, strength, thermal properties, and density of hardened concrete.
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🕑 Reading time: 1 minuteCrushed concrete aggregates also called as recycled concrete aggregates are fragments and pieces of concrete buildings which are demolished or rebuild. These crushed concrete are cleaned from dirt and broken to smaller pieces to manufacture aggregate which is termed as recycled aggregate. Crushed concrete aggregate eliminates the need for disposal by […]
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Crushed aggregates with ... demand while providing good workability. Adjust mixture proportions whenever individual aggregate grading varies during the course of the work. Use the gradations shown in TABLE 1116-2, or other gradation approved by the Engineer.
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Aggregates have a direct and significant impact on the strength, workability, and durability of concrete and asphalt materials, and even the final appearance of structures and pavements. ... The raw, mined materials are crushed to suitable sizes if required, then sorted by size and shape for use as fine or coarse fractions. These mining ...
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Effects of Aggregate Size, Shape, and Surface ... survey was concerned with natural aggregates, and the 1967 survey with crushed aggre-gates. This paper brings together the findings and opinions found in the literature, published ... tion is important for workability, reduced permeability, economy....as the …
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the properties of aggregate: 1. The mineral character of aggregate affects the strength, durability, elasticity of concrete. 2. The surface characteristics of aggregate affects the workability of fresh mass & the bond between the aggregate & cement paste in hardened concrete. If it is rough, workability decreases & bond increases. 3.
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