魏建军 张金喜 王建刚

摘要：以灰砂比0.03、0.05和0.08，粉砂比0、0.05、0.1、0.15和0.2为设计参数，对建筑垃圾回填材料进行设计。通过试验对回填材料的流动性（流动度、泌水率）、无侧限抗压强度以及应力应变曲线、本构关系模型和弹性模量等进行研究。研究结果表明：回填材料的流动度受水固比影响较大，两者接近线性关系；流动度在200～250 mm范围，泌水率在4%～8%之间；回填材料抗压强度与灰砂比和水固比之间存在很好的幂指数关系；回填材料应力应变曲线形状与普通混凝土的相似，在此基础上提出回填材料的本构关系模型；回填材料无侧限抗压强度与弹性模量之间存在很好的指数关系。

关键词：建筑垃圾细料；流动化回填材料；本构关系；应力应变曲线；弹性模量

中图分类号：TU52；U416.212

文献标志码：A 文章编号：1674-4764（2016）03-0096-08

Abstract：A new type of backfill materials using recycled brick and concrete waste as fine aggregates was designed with three cement-to-sand ratios （C/Sa） and five fly ash-to-sand ratios （FA/Sa）. A series of measurements were conducted to investigate the fluidity and bleeding and mechanical properties including uniaxial compressive strength， stress-strain relationship， constitutive relation model and elastic modulus. The results showed fluidity had linear correlation on water-to-solid ratios（W/So）； the range of the bleeding rates was in 4%～8% when the fluidity was within 200～250 mm. The compressive strengths had an exponential relationship to the cement-to-sand ratios and water-to-solid ratios. A constitutive relation model was put forward to describe the stress-strain relationship curve of backfill material on the base of the model of the concrete. The relationship between the unconfined compressive strength and elastic modulus was established， which could be used to calculate the modulus of backfill materials by the compressive strength directly.

Keywords：recycled fine aggregates of brick and concrete waste；flowable backfill materials；constitutive relation；stress-strain relationship curve；elastic modulus

建筑垃圾细料是建筑垃圾在回收利用过程中经分拣，破碎、筛分后得到的粒径范围在0～5 mm的集料。目前，建筑垃圾细料主要来源有两个：一是拆迁后的废砖混结构，二是废弃的混凝土或钢筋混凝土结构。砖混结构生产的建筑垃圾细料主要是破碎的粘土砖和水泥砂浆颗粒和粉末，其中粘土砖的成分较多。废弃混凝土结构生产的建筑垃圾细料中主要是破碎的水泥砂浆颗粒和骨料颗粒以及粉末等（如图1、图2所示）。由砖混结构生产的建筑垃圾细料因其强度低，吸水量大等原因多用于生产再生砖。

流动化回填材料是以0～5 mm细料为基础，加入适当比例的水泥、粉煤灰，加水制备出可以实现自流平和自密实功能的材料。……