粗集料强度对混凝土抗折强度的影响

Experimental Study of Effect of Aggregate Strength on Flexural Strength of Concrete

关键词:  粗集料,混凝土,水泥砂浆基体,抗折强度,弹性模量

Key words:  coarse aggregate,concrete,cement mortar matrix,flexural strength,modulus of (elasticity)

摘要:

试验研究了4种粗集料(碎石、钢集料、砂浆、页岩陶粒)与3种抗压强度等级水泥砂浆基体组合的混凝土的抗折强度及其发展规律.结果表明,粗集料与水泥砂浆基体的协调性对混凝土抗折强度影响十分显著.当粗集料强度和弹性模量与水泥砂浆基体相匹配时,增加粗集料强度可提高混凝土抗折强度,但粗集料强度和弹性模量过高反而会因较大的应力集中而降低混凝土抗折强度;当粗集料强度比水泥砂浆基体抗压强度低时,单纯通过增大水泥砂浆基体抗压强度来提高混凝土抗折强度的效果不明显;粗集料与水泥砂浆基体在抗压强度和弹性模量上的差异对混凝土抗折强度及其发展规律有很大影响.只有在两者相互协调的基础上,才能充分发挥粗集料和水泥砂浆基体的作用.

Abstract:

Flexural strength of concrete and its growth with different cement mortar matrix and reinforced by different coarse aggregate including crushed limestone,steel aggregate,mortar and expanded shale were studied by experiment.The research results show that the coarse aggregate and cement mortar matrix have significant influence on flexural strength of concrete;when the strength and modulus of elasticity of coarse aggregate match to those of cement mortar matrix,it has remarkable effect on flexural strength of concrete by increasing aggregate strength,but when the strength and modulus of elasticity of coarse aggregate is too much high,the flexural strength of concrete will decrease owing to the stress concentration;the effect of enhancing cement mortar matrix compressive strength on improving concrete flexural strength is not prominent either when aggregate strength is lower.The differences in compressive strength and modulus of elasticity between coarse aggregate and cement mortar matrix influence the flexural strength of concrete and its growth significantly;only if the strength and modulus of elasticity of coarse aggregate match those of cement mortar matrix,the better effect could be achieved.