冻融条件下补偿收缩混凝土强度劣化机理试验

冻融是混凝土结构随季节变化所必须经历的阶段,随着冻融次数的增加,混凝土的表观特征和强度将发生退变.采用冻融次数为0、30、50、70、100次,对补偿收缩混凝土进行冻融循环试验,分析补偿收缩混凝土的表面特征和强度劣化趋势,发现随着冻融次数的增加,普通混凝土与补偿收缩混凝土相比,表面破坏更严重,混凝土抗压和抗折强度呈现下降趋势.冻融100次后,普通混凝土抗压、抗折强度分别下降35.2%和44.1%,而补偿收缩混凝土抗压、抗折强度分别下降30.3%和35.3%,说明适当掺入膨胀剂对提高混凝土的抗冻性有一定的作用,有利于控制和降低混凝土冻融环境下强度的退化.

Experimental Research on Deterioration Mechanism of Compensation Shrinkage Concrete Strength under the Condition of Freeze Thawing

Freeze thawing is an obligatory phase of concrete structure changing with the seasons. With the increase of thenumber of freeze thawing, the degeneration of apparent characteristics and strength of the concrete will take place. The 0,30, 50, 70, 100 times of freeze thawing were tested respectively. The cyclic experimental study on shrinkage-compensat-ing concrete was carried out, the analysis on apparent characteristics and strength degradation trend of shrinkage-com-pensating concrete were made. With the increase of number of freeze thawing, more serious damage could be found in or-dinary concrete than shrinkage compensating concrete. Concrete compressive strength and flexural strength decline withthe increase of the number of freeze thawing so that after 100 times of freeze thawing, compressive strength and flexuralstrength of ordinary concrete decline 35.2% and 44.1% respectively, and that of the shrinkage compensating concrete de-cline 30.3% and 35.3% respectively. Appropriate adding of expansive agent show certain intensifing effect on enhancingconcrete frost-resistance, and could benefit the control and reduction of the deterioration of concrete strength.