固化建筑渣土力学和路用性能试验研究

Experimental Study on Mechanical Properties and Road Properties of Solidified Construction Waste Soil

为解决建筑渣土处置难、堆弃难、资源化程度低等问题,本文提出采用固化剂固化建筑渣土。本文对比分析了水泥掺量、固化剂掺量、养护龄期对固化建筑渣土无侧限抗压强度、劈裂抗拉强度、水稳性、抗冻融性能、抗干缩性能的影响规律,并通过SEM和XRD试验结果分析了固化剂协同水泥固化的固化机理。结果表明,当水泥质量掺量为7%且固化剂质量掺量为3%时,固化建筑渣土28 d无侧限抗压强度为6.91 MPa、劈裂抗拉强度为0.98 MPa、水稳系数91.52%,较水泥质量掺量为10%的对比件分别增加15.7%、31.2%和12.2%;固化剂的掺入具有提高水泥固化土抗干缩性能的作用;冻融循环10次后,固化建筑渣土试件较水泥固化对比试件质量损失率降低44.6%,残余强度增加34.9%。固化剂协同水泥水化反应生成的C-S-H和C-A-H胶凝物质使土颗粒团聚成团粒结构,形成网络骨架提供强度;固化剂中的SiO_(2)、Al_(2)O_(3)减小了土颗粒间的自由水和吸附水含量,加入固化剂后固化土的强度和路用性能得到增强和改善。研究结果为固化建筑渣土在路基中的应用提供理论基础。

In order to solve the problems of difficult treatment of construction residue and low degree of resource utilization,this paper proposes to use a curing agent to solidify construction residue.In this paper,the effects of cement content,curing agent content,and curing age on the unconfined compressive strength,splitting tensile strength,water stability,freeze-thaw resistance,and dry shrinkage resistance of solidified soil were analyzed,and the curing mechanism of co-curing agent and cement was revealed by SEM and XRD tests.The results show that,when the cement content is 7%,and the content of curing agent is 3%,the unconfined compressive strength of solidified soil residue is 6.91 MPa,the splitting tensile strength is 0.98 MPa,and the hydraulic stability coefficient is 91.52%for 28 d,compared with cement curing,which increases by 15.7%,31.2%and 12.2%,respectively.The incorporation of the curing agent has the effect of improving the dry shrinkage resistance of solidified soil.After 10 freeze-thaw cycles,the mass loss rate of solidified soil decreases by 44.6%and the residual strength increases by 34.9%compared with that of cement cured specimens.The C-S-H and C-A-H cementitious substances generated by the cement hydration reaction of the curing agent make the soil particles agglomerate into a granular structure and form a network skeleton to provide strength.The SiO_(2)and Al_(2)O_(3)in the curing agent reduce the content of free water and adsorbed water between the soil particles,and the strength and road performance of the solidified soil is enhanced and improved after the addition of the curing agent.The results of the study provide a theoretical basis for the application of cured construction residue soil in roadbeds.