再生混凝土基本力学性能试验及其影响因素研究

Experimental research on basic mechanical characteristics of recycled aggregate concrete and influencing factors

以武汉某城市道路维修所废弃,经现场钻芯取样推定原生强度等级为C55的混凝土,作为再生粗骨料来源,设计4种取代率(0、50%、75%、100%)和3种水灰比(0.38、0.42、0.46)共108个试件,对再生混凝土的立方体抗压、立方体劈裂抗拉、抗折强度开展有关试验研究,揭示了取代率和水灰比影响下的再生混凝土力学性能变化规律和影响机理。研究表明:随着取代率的不断增大,再生骨料在构建再生混凝土骨架空间中的分布越发广泛,对再生混凝土力学性能和工作性能造成了不利影响;再生混凝土破坏机理的核心就是,残余外包裹砂浆在水泥砂浆黏结界面的占比,对降低实际水灰比提高再生混凝土强度的贡献,小于再生骨料缺陷降低黏结界面承载力带来强度减小的损失;原生服役强度越高,黏结界面原始缺陷和承载力的薄弱就相应减少。

The concrete which is abandoned by the city road maintenance in wuhan,the field more constructive native to C55concrete strength grade,as a source of recycled coarse aggregate,which had been designed four kinds of replacement ratio(0,50%,75%,50%)and three kinds of water cement ratio(0.38,0.42,0.46),a total of108specimens of recycled concrete cube cube compressive strength,splitting tensile and flexural strength to carry out the relevant experimental study,revealing the replacement ratio and under the influence of water-cement ratio of recycled concrete mechanical properties change rule and influence mechanism.Research shows that:with the increasing of replacement ratio,recycled aggregates in the construction of recycled concrete skeleton more widely distributed in space,on the recycled concrete mechanical properties and working performance caused adverse effect;Outside the core of the recycled concrete failure mechanism is,residual wrapped slurry in the proportion of cement mortar bonding interface,to reduce the actual strength of recycled concrete water-cement ratio increased,the contribution of less than the recycled aggregates defects reduce bring strength in order to reduce the loss of the bonding interface bearing capacity;The higher the original service strength,the less the original defect and the weak bearing capacity of the adhesive interface.