废砖再生集料强化对再生混凝土的性能影响

Effect of reinforced recycled brick aggregate on performance of recycled concrete

将废弃黏土砖制成再生集料,代替部分天然集料制备再生混凝土,研究了4种强化剂对废砖再生粗集料基本性能和再生混凝土性能的影响,利用扫描电镜观察了再生混凝土的微观形貌。结果表明,水泥类浆液对再生集料基本性能的影响具有相似的规律;水玻璃溶液不仅能增大再生集料的表观密度,降低压碎值,还能降低再生集料的吸水率,水玻璃溶液浓度为15%最宜;废砖再生集料取代率超过40%后,再生混凝土28d抗压强度达不到设计标准,经过强化的再生集料混凝土抗压强度最多可提高3.1MPa,水玻璃溶液的强化效果最好。经水玻璃溶液处理后的再生集料混凝土,其内部水化反应更完全,水化产物较多,强度也更高。

In this paper,the recycled concrete is prepared by making recycled clay bricks into recycled aggregates instead of some natu⁃ral aggregates.The effects of four kinds of strengthening agents on the basic properties of recycled coarse aggregates and recycled con⁃crete are studied.The microstructure of recycled concrete was observed by scanning electron microscope.The results show that the ef⁃fects of cement slurry on the basic properties of the regenerated aggregate are similar.The water glass solution can not only increase the apparent density and reduce the crushing value of the recycled aggregate,but also reduce the water absorption of the recycled aggregate.The water glass solution concentration of 15%is the best.When the replacement rate of recycled brick aggregate exceeds 40%,the com⁃pressive strength of recycled concrete in 28d fails to reach the design standard.The compressive strength of reinforced recycled concrete can be increased by up to 3.1MPa,and the strengthening effect of sodium silicate solution is the best.The recycled aggregate concrete treated with water glass solution has more complete internal hydration reaction,more hydration products and higher strength.