砖混类建筑垃圾的资源化利用技术研究与应用

Resource utilization technology research and application of brick-mixed construction waste

利用砖混类建筑垃圾制备再生骨料水泥稳定无机料,进行击实试验、强度试验及抗冻融性试验,开展全再生基层道路试验段的铺设及运行3年后的效果评估;利用冗余土制备流态回填材料,并介绍了工程应用情况。结果表明:4%~7%水泥掺量的砖混类再生骨料水泥稳定无机料7 d无侧限抗压强度可达到3.0~5.5 MPa,而且28 d养护龄期5次冻融后强度保持率均大于90%;试验路运行3年后基层整体性较好,芯样强度及弹性模量满足设计要求。水泥对流态回填料强度起关键作用,粉煤灰能提高早期强度;除尘微粉可替代粉煤灰用于流态回填材料的制备,水泥用量50 kg/m^(3),微粉用量80 kg/m^(3)时,流态回填料泌水率小于8%,28 d抗压强度大于0.4 MPa,满足一般回填工程的技术要求。

Recycled aggregate cement stabilized inorganic materials using recycled aggregate from brick-mixed construction waste disposal were prepared,impact tests,strength tests,and freeze-thaw resistance tests were conducted and a full-recycled base layer road test section was constructed and its performance was evaluated after three years of operation.Flowable backfill materials were prepared by using redundant soil and its engineering application conditions are introduced.The results show that the 7 d unconfined compressive strength of the recycled aggregate cement stabilized inorganic materials with a cement content of 4%to 7%can reach 3.0 to 5.5 MPa.Moreover,the strength retention rate of 5 freeze-thaw cycles during the 28 day curing period is greater than 90%.After three years of operation,the test section has good overall integrity,and the core sample strength and elastic modulus meet the design requirements.The results show that cement plays a key role in the strength of the flowable backfill material,and fly ash can improve the early strength.Dust micro-powder can replace fly ash for flowable backfill materials.When the cement content is 50 kg/m^(3)and the micro-powder content is 80 kg/m^(3),the bleeding rate of the flowable backfill material is less than 8%,and the strength is greater than 0.4 MPa,meeting the technical requirements of general backfilling projects.