高土石坝防渗墙混凝土性能试验

结合工程实践,对高土石坝防渗墙混凝土的性能进行试验研究。采用3种比表面积的低热水泥、不同的粉煤灰掺量、聚羧酸系减水剂和引气剂设计了12种配合比,并进行了混凝土性能试验。试验结果表明,采用粗颗粒低热水泥、高性能减水剂和引气剂以及掺40%质量分数的粉煤灰,可以配制出弹性模量与抗压强度之比仅为710的高强度、低弹性模量且工作性能优良的防渗墙混凝土。此外,该混凝土28 d强度仅为24.8MPa,而90 d强度高达45.8MPa,早期强度增长非常缓慢,有利于工程施工。

Experiment on the concrete properties of cutoff wall of high earth-rock dam

The concrete properties of the cutoff wall of a high earth-rock dam were studied and conclusions were made with consideration of experience gained in engineering practice.Twelve mix proportions were designed to test the concrete properties using low thermal cement with three different specific surface areas and different contents of fly ash,polycarboxylic acid type water-reducers and air-entraining agents.The experimental results indicate that a mix of coarse-grained low thermal cement,a high performance water reducer,an air-entraining agent,and a 40% content of fly ash can create high-strength cutoff wall concrete with a low elastic modulus.The ratio of the elastic modulus to compressive strength of the concrete is only 710,and its workability is significantly improved. Moreover,the early strength of cement develops slowly: the compressive strength of 28 days is 24.8 MPa and that of 90 days is 45.8 MPa,which benefits engineering construction.