结构用橡胶集料混凝土受压全曲线试验及其本构模型

Compression test on curves and constitutive model of crumb rubber concrete for structural purposes

针对结构用橡胶集料混凝土(CRC)应保证与普通混凝土等强,而此类CRC单轴受压全曲线试验研究有限,尚无较成熟单轴受压本构模型的情况,分别进行了3组粒径为1~2mm、掺量为0~100kg·m-3的CRC立方体试块单轴受压试验及棱柱体试块受压应力-应变全曲线试验。结果表明:通过综合采用NaOH碱溶液处理橡胶颗粒及配合比优化设计的方法,可以精确控制CRC与普通混凝土等强,且峰值应变及极限应变明显增加,试块破坏过程温和缓慢,破坏时完整性较好。同时,现有的普通CRC单轴受压本构模型不适用于此类结构用CRC,而普通混凝土单轴受压Carreira-Chu本构模型虽与试验曲线吻合尚可,但其对CRC的适用条件有待考证。最后,通过曲线拟合试验数据,得到以过镇海模型为基础的结构用CRC本构模型参数的建议取值,以用于此类结构构件的分析与设计。

Crumb rubber concrete（CRC）used in structures should be designed with equal strength as ordinary concrete,but the study on uniaxial compression test and constitutive model of this kind of concrete are limited.This paper conducted three groups of compression test with CRC cubes and prisms.The size was 1-2 mm and the rubber content ranged from 0 to 100 kg·m-3.The results show that by pretreating the rubber particles with NaOH aqueous alkali and optimizing the mix proportion of concrete,CRC can accurately reach the same strength as ordinary concrete,while the peak strain and the ultimate strain increase obviously.The failure process of CRC specimens are mild and slow,and the specimens keep their integrity well at the failure moment.At the same time,the existing ordinary CRC constitutive models under uniaxial compression are not suitable for CRC in this study.Although Carreira-Chu constitutive model of ordinary concrete is consistent with the experimental curves,the scope of application for CRC need to be verified.Finally,through the curve fitting,the proposed values of the constitutive parameters of CRC based on the GZH model were obtained and applied in the analysis and design of CRC structural members.