建筑垃圾再生微粉/硅锰渣粉复合辅助性胶凝材料的制备和性能

Preparation and Properties of Compound Supplementary Cementitious Materials of Recycled Micro-powder from Construction Waste and Silicon-manganese Slag Powder

再生微粉是目前建筑垃圾高效资源化的有效途径之一,但其需水量高、水化活性偏低问题仍有待解决。提出利用硅锰渣粉与再生微粉复合制备建筑垃圾再生微粉/硅锰渣粉复合辅助性胶凝材料。结果表明:随着硅锰渣粉掺量增加,复合辅助性胶凝材料流动度比和活性指数均大幅提高,当硅锰渣粉掺量30%(质量分数)时,复合辅助性胶凝材料胶砂流动度比达98%,28 d活性指数达98%;复合辅助性胶凝材料与再生微粉相比,水化早期反应快,7 d累积水化放热更高,说明其早期水化速率更高;随着硅锰渣粉替代再生微粉比例增加,胶凝材料体系净浆孔隙率降低、微纳米孔含量增加;复合辅助性胶凝材料水化消耗了更多的Ca(OH)_(2)形成C-S-H凝胶,故基体致密程度提高。

Recycled micro-powder(RP)is one of the most effective ways to utilize construction waste with high value and high efficiency,but the high water demand and low hydration activity of RP remain to be solved.In this study,a compound supplementary cementitious material(CM)of recycled micro-powder from construction waste and silicon-manganese slag powder(SM)was prepared.Results show that the fluidity ratio of CM and the activity index of the CM are greatly improved with the increase of SM content in CM.When the content of SM was 30%(mass fraction),fluidity ratio of CM could reach 98%and the 28 d activity index could be 98%.Compared with recycled micro-powders,hydration rate of the prepared CM was fast in the early hydration stage.However,the 7 d cumulative heat release of CM hydration was higher than that of RP,indicating that the early hydration rate of SM was higher.The porosity of hardened cement paste containing CM decreased and the content of micro-and nano-pores increased with the increase of substituting SM for RP.More Ca(OH)_(2) is consumed in hydration of CM to form C-S-H gel,so the density of matrix was improved.