掺疏浚底泥砂浆的力学性能及微观结构

Mechanical properties and microstructure of mortar mixed with dredged sediment

针对疏浚底泥处理的减量化、资源化和无害化需求,将不同处理方式的太湖底泥作为掺合料取代砂浆中的水泥,以促进固废资源再利用。通过抗压抗折强度、吸水率试验及XRD、TG微观测试分析,深入研究了底泥处理方式和掺量对水泥砂浆各项性能的影响规律及机理。研究结果表明,随着底泥掺量增加,砂浆强度逐渐降低、吸水率升高,当掺量超过20%时,变化更为明显。经高温煅烧后,底泥的火山灰活性增强,与氢氧化钙反应生成更多的水化产物,相同掺量下各种测试性能虽较优于未煅烧底泥,但需耗费更多的热能。微观测试结果与宏观性能测试结果吻合良好,进一步揭示了掺疏浚底泥砂浆力学性能演化的内在机制。由此可根据不同工程需求,处理利用底泥,以促进环境与资源可持续发展。

In view of the demand for reduction,recycling and harmlessness of dredged sediment treatment,Taihu Lake sediments with different treatment methods were used as admixtures to replace cement in mortar to promote the reuse of solid waste resources.Through compressive and flexural strength,water absorption test and XRD,TG microscopic test and analysis,the influence law and mechanism of sediment treatment method and dosage on the properties of cement mortar were deeply studied.The research results showed that with the increase of sediment content,the mortar strength gradually decreases and the water absorption rate increased,and when the content exceeded 20%,the change was more obvious.After high temperature calcination,the pozzolanic activity of the sediment was enhanced,and it reacted with calcium hydroxide to generate more hydration products.Although the various test performances were better than those of the uncalcined sediment at the same dosage,it needed more heat energy.The microscopic test results were in good agreement with the macroscopic performance test results,which further revealed the internal mechanism of the evolution of the mechanical properties of the dredged bottom mud mortar.In this way,the sediment could be processed and utilized according to different engineering needs,so as to promoted the sustainable development of the environment and resources.