水泥受潮对动荷载下混凝土力学特性的影响

Influence of damp cement on concrete mechanical properties under dynamic loading

以往关于混凝土力学特性的研究多是在配制混凝土的水泥未受潮劣化的前提下进行的,未充分考虑水泥受潮对混凝土力学性能的影响。借助MTS815试验系统,对同一受潮水泥制作的C50、C60混凝土试件以及未受潮水泥制作的C40、C50和C60混凝土试件进行加载速率从0.002~7 mm/s的动态单轴压缩试验,系统研究了高强度等级水泥受潮对动态加载下混凝土抗压强度、峰值应变、弹性模量和应力-应变关系曲线等力学特性的影响。结果表明：在静态及较高加载速率下水泥受潮对混凝土强度和峰值应变的影响较大,中低加载速率下水泥受潮对强度和峰值应变的影响相对较小;加载速率对受潮水泥配制混凝土割线模量的影响相对较小,水泥的受潮会造成混凝土强度的降低,但不改变混凝土的破坏形式。

Previous studied on the mechanical properties of concrete were based on the premise that the cement was dry and neglecting the influence of cement moisture,which was inconsistent with the reality.Using the MTS815 test system,the dynamic loading uniaxial compression test of concrete specimens（C50 and C60）made of damp cement and specimens（C40,C50 and C60）made of dry cement were undertaken,with the loading rate varying from 0.002 mm/s to 7 mm/s.Contrasted with the mechanical properties of specimens which made of dry cement,the mechanical properties of strength,peak strain,elastic modulus and the stress-strain curves of concrete specimens made of damp cement had been systematically studied.The study revealed that,the influence of damp cement on strength and peak strains of concrete were greater under static or high loading rates compared with strength and peak strains under low loading rates,and the impact of damp cement on secant modulus of concrete was relatively small.Though damp cement results in the reduction of the concrete strength,it did not change the destruction form of concrete.