砂石含泥量对掺聚羧酸减水剂隧道用泵送混凝土性能影响

混凝土主要由砂石料、水泥、掺合料、水、外加剂等组合而成,其中砂石料作为骨架结构,占了混凝土体积的绝大部分,砂石料含泥量的大小直接影响混凝土工作性能和强度。混凝土中聚羧酸减水剂对砂石含泥量十分敏感,含泥量的变化直接影响聚羧酸减水剂的减水效果和保坍效果。目前除了加强对砂石料的水洗,降低砂石料含泥量外,还没有一种简单有效的措施来解决此问题,只能通过适当提高减水剂的掺量来改善,但提高减水剂掺量的同时也提高了混凝土的成本,而且操作过程中容易造成泵送混凝土堵管情况发生。

Influence of Sand and Mud Content on Performance of Pumped Concrete Mixed with Polycarboxylic Acid Water Reducer

Concrete is mainly composed of sandstone,cement,admixture,water,additives,etc.Among them,sandstone as the skeleton structure,accounting for the vast majority of the volume of concrete,the size of sandstone mud directly affects the concrete work performance and strength.The polycarboxylic acid water-reducing agent in concrete is very sensitive to the sand and mud content.The change of the mud content directly affects the water-reducing effect and slump retention effect of the polycarboxylic acid water-reducing agent.At present,in addition to strengthening the washing of sand and gravel materials and reducing the mud content of sand and gravel materials,there is no simple and effective measure to solve this problem.It can only be improved by appropriately increasing the amount of water reducing agent,but while increasing the amount of water reducing agent,it also increases the cost of concrete,and it is easy to cause blocking of the pumped concrete during operation.