稻壳灰和电石渣改性膨胀土力学性能及作用机理研究

采用稻壳灰(RHA)和电石渣(CCR)复合胶凝材料对膨胀土进行改良。通过强度试验确定了RHA和CCR的最佳配比为65∶35。通过对RHA-CCR改良膨胀土试验研究发现,随着RHA-CCR掺量、养护时间和初始含水率的增加,膨胀率与膨胀力显著降低,添加RHA-CCR后无侧限抗压强度显著提高。从强度提高的角度出发,建议RHA-CCR掺量为15%、初始含水率为最佳含水率的1.2倍来改良膨胀土。探讨了RHA-CCR改良膨胀土的作用机理,发现其机理包括置换作用、胶凝反应和离子交换。

Study on Mechanical Properties and Mechanism of Expansive Soil Modified by RHA and CCR

Rice husk ash(RHA)and calcium carbide residue(CCR)composite cementing materials were used to improve expansive soil.The optimum ratio of RHA and CCR is 65∶35.Through the experimental study on RHA-CCR modified expansive soil,it is found that with the increase of RHA-CCR content,curing time and initial water content,the expansion rate and expansion force are significantly reduced,and the unconfined compressive strength is significantly increased after adding RHA-CCR.From the perspective of strength improvement,it is suggested to improve expansive soil by adding 15% RHA-CCR and 1.2 times of the optimal water content.The mechanism of RHA-CCR improved expansive soil was discussed,including displacement,cementation and ion exchange.