再生骨料强化及再生混凝土性能研究

Study on reinforcement of recycled aggregate and properties of recycled concrete

为了改善废弃混凝土骨料压碎值和吸水率较高的问题,采用水玻璃和硅烷偶联剂对废弃混凝土骨料进行化学强化,研究了强化前后压碎值和吸水率的变化规律,通过SEM电镜扫描得到强化前后的骨料表面形貌,明确了强化原因,同时将强化废弃混凝土全部代替天然骨料配制混凝土试件,分析了废弃混凝土骨料经强化后再生混凝土的力学性能和耐久性的变化规律。试验结果表明:经过强化后的废弃混凝土骨料吸水率和压碎值均得到明显改善,且提高了再生混凝土性能,降低了混凝土的孔隙率使其更加密实。水玻璃的强化效果优于硅烷偶联剂,水玻璃强化浓度宜大于20%,硅烷偶联剂掺入量宜大于4%。

In order to improve the problem of insufficient crushing value and water absorption rate of waste concrete aggregate,it adopts sodium silicate and silane coupling agent to carry out chemical strengthening of waste concrete aggregate.The changes of crushing value and water absorption before and after strengthening were studied.The surface morphology of aggregate before and after strengthening was obtained by scanning electron microscope,and the reasons for strengthening were clarified.In addition,reinforced waste concrete was substituted for natural aggregate to prepare concrete specimens,and the change rules of mechanical properties and durability of recycled concrete after the reinforced waste concrete aggregate were analyzed.The experimental results show that water absorption and crushing value of waste concrete aggregate are significantly improved after chemical strengthening.It improves the performance of recycled concrete and reduces the porosity of concrete to make it more compact.The strengthening effect of sodium silicate is better than that of silane coupling agent.The concentration of sodium silicate should be more than 20%,and the incorporation of silane coupling agent should be more than 4%.