轻质多孔混凝土受压应力—应变全曲线试验研究

Experimental study on the total stress-strain curve of porous lightweight concrete

通过对这两种轻质多孔混凝土材料进行基本力学性能试验,就其弹性模量及应力—应变全曲线等进行了研究与探讨。试验结果表明:相对于普通混凝土而言,轻质多孔混凝土的立方体抗压强度、棱柱体抗压强度、弹性模量等均要小一个量级,而峰值应变却比前者大30%～40%。单轴受压应力—应变曲线到达峰值应力前近似按线性比例增加,塑性变形很小;峰值应力后,迅速跌落;跌落至其残余强度后,出现缓慢降落的斜直线段。材料在整个受压破坏过程中,呈现出低强度弹脆性力学性能。在试验研究与理论分析的基础上,采用上升、下降和斜直线三段曲线拟合了轻质多孔混凝土的单轴受压应力—应变关系,给出了具有明确物理意义的轻质多孔混凝土材料单轴受压统一本构模型,为轻质多孔混凝土在抗震结构中的广泛应用提供了有力的试验依据。

The mechanical properties of porous lightweight concrete（PLC） have seldom been investigated in the world.In this paper,two groups of experiment were carried out to study the mechanical properties of PLC,including young＇s modulus,strain at peak stress,etc.;and one is about autoclaved aerated concrete,the other about foamed concrete.Comparison of the test results of this study and other correlative literature were given.And the test and analysis show that：the cubic strength,prismatic strength,young＇s modulus,etc of ordinary concrete are about one order of magnitude smaller than those of PLC,but its strain at peak stress is 30% ～ 40% less than the latter.Before the peak stress,the stress-strain curve of PLC is approximately straight line.After the peak stress,the shape of the curve becomes very steep.After the residual strength,the slow descending curve is appeared.From the process of the compressive failure,it can be seen that the material properties are strength-low,elastic and brittle.Based on experimental study and theoretical analysis,the three-segment constitutive model,which is univocal parameters in physics,is put forward to simulate the compression action of PLC.These works also serve as the positive application of PLC on the seismic structure with providing experimental evidence.