Aug 11, 2018· When the aggregate is sieved through 4.75mm sieve, the aggregate retained is called coarse aggregate. Gravel, cobble and boulders come under this category. The maximum size aggregate used may be dependent upon some conditions. In general, 40mm size aggregate used for normal strengths and 20mm size is used for high strength concrete.
Aggregate is classified as two different types, coarse and fine. Coarse aggregate is usually greater than 4.75 mm (retained on a No. 4 sieve), while fine aggregate is less than 4.75 mm (passing the No. 4 sieve). The compressive aggregate strength is an important factor in the selection of aggregate.
Shape And Size Effect On Concrete Strength. Aggregates shape and size has a strong influence on properties of concrete. Rough surface textured particles increase the compressive strength of concrete up to 20-30%, instead of using natural gravels that is obtained from river beds.
coarse aggregates in high strength concrete Given the critical role that the interfacial transition plays in high-strength concrete, the mechanical properties of coarse aggregate will have a more pronounced effect than they would in conventional-strength concrete.
Effect of Coarse Aggregate on Strength of Concrete Coarse aggregate makes up about 75% of concrete by volume. Strength of concrete is also affected by the properties of coarse aggregates besides water-cement ratio and other properties. The lower the water to cement ratio, the more the effect of coarse aggregates on the strength of concrete.
Using larger coarse aggregate typically lowers the cost of a concrete mix by reducing cement requirements, the most costly ingredient. Less cement (within reasonable limits for durability) will mean less water if the water-cement (w/c) ratio is kept constant.
Ordinary crushed stone with size 20mm was used as coarse aggregate in concrete mixes. They generally possess all the essential qualities of a good building stone showing very high crushing strength, low absorption value and least porosity. In general, water fit for drinking is suitable for mixing concrete.
Sep 02, 2014· Originally Answered: What is the effect of coarse aggregate size in compressive strength of concrete ? The shape and size of aggregate have a significant impact on compressive strength of concrete. Larger the aggregate, greater is the tendency of blocking the bleed water and thus weaker is the transition zone (higher w/c ratio in area around the aggregate).
Coarse aggregates (Fig. 5-2) consist of one or a com-CHAPTER 5 Aggregates for Concrete bination of gravels or crushed stone with particles predominantly larger than 5 mm (0.2 in.) and generally between 9.5 mm and 37.5 mm (3⁄ 8 in. and 11⁄ 2 in.). Some natural aggregate deposits, called …