The Study On Impact Of Coarse Aggregate And Cementing Material On Performance Of Self-compacting Concrete

Coarse aggregate is one of the main components of concrete and it has important influence on the performance of concrete.The freedom or constraint accumulation of the coarse aggregate formed the main skeleton concrete structure and contribute to the strength of concrete.Reduction of Coarse aggregate will take effects on the compressive strength of concrete.Concrete must have a certain liquidity,because it is pumped and transported.At the same time,the new construction methods of prefabricated concrete structure and self-compacting concrete pile do not leave the higher liquidity.This concrete named self-compacting concrete.For concrete with nodes casting purposes,self compensation material performance should be considered. What's more, for the higher liquidity self-compacting concrete filled, it has coarse aggregate with large surface and filled gap .The effective bonding is formed between aggregate and surface area and it is very important.So it has enough cementing materials to be used and form bonding effect with coarse aggregate,Comparing with ordinary concrete, higher liquidity self-compacting concrete need more cementing materialslarge.So,it is very important significance to study the effect law of the dosage of coarse aggregate and cementing materials for basic mechanical properties of high liquidity self-compacting concrete.This article adopts the method of test and theoretical analysis.It used self-compacting concrete with two kinds of admixture or no admixture.By reducing the dosage of coarse aggregate to test the 14d and 28d compressive strength of concrete,we analyzed the influence law of compressive strength of self-compacting concrete of reducing coarse aggregate.When adding to a kind of mixture, and gradually increasing cementing material consumption,we tested the time of flowing past the "V" shaped funnel and T50,and the height of "U" shaped box filling and analyzed the dosage of cementing material effect on the working properties of self-compacting concrete.What's more,we also tested the compressive strength and splitting tensile strength of 3d and 7d and 14d and 28d concrete specimen,and explores the dosage of cementing material effect on the mechanical properties.The main contents are as follows:(1)When not adding admixture,as self-compacting concrete of lower strength ,the concrete compressive strength fluctuated change with reducing the dosage of gravel and it is to improve after lower first.At the same time,according to the reduction of coarse aggregate,the raise or lower magnitude of the compressive strength is also different.But it is no more than 10%.As self-compacting concrete of higher strength,concrete compressive strength presents the downward trend.At the same time,according to the reduction of coarse aggregate, the decreasing amplitude of the compressive strength is lower and the amplitude are less than 10%.(2)When double mixing fly ash and mineral powder,as self-compacting concrete of lower strength ,the concrete compressive strength also fluctuated change with reducing the dosage of gravel and the magnitude is no more than 10%.For self-compacting concrete of higher strength,concrete compressive strength presents the downward trend and the decreasing amplitude of the compressive strength is less than 5%.(3)With the increase of dosage of cementing material, the work properties of the self-compacting concrete will take certain influence.when the cementing material dosage is too little,the flow and populate performance will be bad.With the increase of gelled material, slurry can improve the effect of lubrication between aggregate and working performance of higher liquidity self-compacting concrete become better.(4)The amount of cementing material of self-compacting concrete will have impact on compressive strength and splitting tensile strength.With the increase of dosage of comenting material, concrete compressive strength is increased gradually,but increasing modestly and change trend is more gently. Splitting tensile strength of concrete began to rise, but when the dosage of cementing material over a certain amount, splitting tensile strength will take a tendency to decrease.Single mixed with mineral powder or fly ash , the splitting strength along with the age growth law is roughly the same.Concrete mixed with mineral powder, the early strength is higher.Concrete mixed with fly ash,later strength is higher.