碳化与冻融交替作用下的混凝土抗压强度

通过室内单一碳化、单一冻融,以及碳化与冻融交替作用下的混凝土耐久性循环试验,对比分析了混凝土相对抗压强度、相对动弹性模量和碳化深度等指标的变化规律.结果表明:在碳化与冻融交替作用下,混凝土相对抗压强度要比单一冻融作用时大,但增加程度有限;混凝土相对动弹性模量要比单一冻融作用时小,碳化深度则比单一碳化作用时大.碳化与冻融交替作用下的混凝土抗冻耐久性较之单一冻融作用下有所下降,抗碳化能力较之单一碳化作用下有所减弱.最后建立了碳化与冻融交替作用下以碳化时间和冻融循环次数为变量的混凝土抗压强度拟合模型.

Compressive Strength of Concrete Exposed to Alternate Carbonation and Freezing Thawing Cycles

Based on carbonation only test, freezing thawing cycle only test and alternate test between carbonation and freezing thawing cycles, relative compressive strength, relative dynamic modulus of elasticity and carbonation depth of concrete were measured and analyzed. Test data show that for the alternate actions between carbonation and freezing thawing cycles, relative compressive strength of concrete is higher than that exposed to freezing thawing cycle only process, but the increase is limited; its relative dynamic modulus of elasticity is lower than that exposed to freezing thawing cycle only process; whereas its carbonation depth is larger than that exposed to carbonation only process. The frost resistance and carbonation resistance of concrete decrease compared to that exposed to freezing thawing cycle only and carbonation only processes, respectively. Finally, a compressive strength fitting model subjected to the alternate actions between carbonation and freezing thawing cycles is established, in which two independent variables(carbonation time and number of freezing thawing cycles) are taken into account.