稻壳灰-脱硫灰-钢渣复合胶凝材料的制备及在固化土中的应用

Preparation of rice husk ash-desulfurization ash-steel slag composite cementitious material and its application in solidified soil

为扩展固体废弃物的资源化利用途径,以稻壳灰、脱硫灰、钢渣为主要原材料,辅以适当的激发剂,制备复合胶凝材料。研究不同组成的复合胶凝材料的流动性、抗压强度,借助XRD和SEM对胶凝材料的水化机理进行分析,探究了复合胶凝材料固化页岩土的强度发展规律。研究表明:当稻壳灰、脱硫灰和钢渣按照1∶3∶1的比例,并外掺8%的激发剂,制备的胶凝材料的净浆流动度可达180mm, 28d抗压强度达到24.28MPa;在激发剂的作用下,稻壳灰-脱硫灰-钢渣相互促进水化,浆体的早期水化产物主要是C-S-H凝胶和钙矾石;在水化后期,水化产物的种类和数量增加,钙矾石、钙沸石以及C-S-H凝胶相互搭接、嵌合,使浆体的结构更加致密;当复合胶凝材料掺量为页岩土质量的15%时,固化土28d强度可稳定达到0.7MPa以上,满足一般填筑工程材料的强度要求。

In order to expand the resource utilization of solid waste, composite cementitious materials are prepared with rice husk ash, desulfurization ash and steel slag as main raw materials and appropriate activator. The fluidity and compressive strength of composite cementitious materials with different compositions are studied. The hydration mechanism of cementitious materials is analyzed by XRD and SEM, and the strength development law of shale soil solidified by composite cementitious materials is explored.The results show that when the ratio of rice husk ash, desulfurization ash and steel slag is 1∶3∶1, and 8% activator is added, the fluidity of the prepared cementitious material can reach 180 mm, and the 28 d compressive strength can reach 24.28 MPa. Under the action of activator, the rice husk ash-desulfurization ash-steel slag promote hydration, and the early hydration products of slurry are mainly C-S-H gel and ettringite. At the later stage of hydration, the types and quantities of hydration products increase, and ettringite, scolecite and C-S-H gel overlap and embed with each other, making the structure of slurry more compact. When the content of composite cementing material is 15% of shale soil mass, the 28 d strength of solidified soil can stably reach above 0.7 MPa, meeting the strength requirements of general filling engineering materials.