三级配混凝土抗压强度尺寸效应的试验研究

为系统研究强度等级和矿渣掺量对混凝土抗压强度尺寸效应的影响,分别对试件尺寸为200,250 mm和300 mm,矿渣掺量为0,30%,40%,50%和60%,强度等级为C15、C20和C25的三级配混凝土立方体试件进行了抗压强度试验。结果表明:三级配混凝土的抗压强度存在尺寸效应现象,其中强度等级对尺寸效应的影响比较显著,表现为尺寸效应现象随强度等级的提高呈显著增加的趋势;矿渣掺量的变化对混凝土抗压强度的尺寸效应也有一定的影响,但是相比强度等级,其效果不明显。最后,结合Bazant尺寸效应律公式,计算得出不同强度等级、不同矿渣掺量的三级配混凝土抗压强度的临界尺寸Dcr和临界强度fcr,可为矿渣混凝土的力学性能试验研究和工程应用提供参考。

Experimental study on size effect of compressive strength of three graded concrete

In order to research the influence of strength grade and slag content on size effect of concrete compressive strength, the cube compressive strength test of 45 groups of three graded concrete specimens was carried out. The specimens include three sizes of 200mm, 250mm and 300mm, five kinds of slag content of 0%, 30%, 40%, 50% and 60%, three strength grades of C15, C20 and C25.The test results show that the compressive strength of three graded concrete has obvious size effect, and the general trend is that the size effect becomes more and more obvious with the increase of the intensity level. However, the effect of slag content on the size effect is not so significant as the intensity level. At last, in combination with Bazant size effect law formula, the critical size and critical strength of three graded concrete with different slag contents and different strength grades were calculated, which can provide reference for the mechanical performance test research and engineering application of slag concrete.