两种生产工艺机制砂掺配对混凝土性能的影响

本文针对湿法制砂得到的水洗砂和干法制砂得到的风吸砂掺配比例问题,分析了水洗砂和风吸砂的差异,研究了不同生产工艺机制砂掺配比例对铁路工程泵送混凝土工作性能、抗压强度、电通量和碳化性能的影响。结果表明:两种机制砂级配和压碎值相近,风吸砂略粗,石粉含量较低,水洗砂较干净,需水量比较低;随着水洗砂掺配比例的提高,混凝土减水剂掺量呈现降低的趋势,混凝土流动性得到改善,采用泵送施工工艺的情况下,推荐机制砂掺配比例水洗砂/风吸砂为7/3;随着水洗砂掺配比例的增加,混凝土抗压强度逐渐增大,电通量呈现降低趋势,抗碳化性能提高,主要原因是水洗砂掺配比例增加,混凝土密实性得到提高。研究工作能够推进机制砂混凝土应用,提高机制砂混凝土质量。

Effects of Blending of Machine-made Sand Manufactured with two Production Technologies on Concrete Performance

This paper analyzes the difference between water-washed sand and wind-sucked sand for the blending proportion of the water-washed sand obtained by wet process and the wind-sucked sand obtained by dry process,and studies the effects of the blending proportion of the sand manufactured with different production technologies on the working performance,compressive strength,electric flux and carbonization performance of the pumped concrete for railway engineering.The results show that the sand gradation and crushing value of the two types of machine-made sand are similar,and the wind-induced sand is slightly thicker with a lower stone powder content while the water-washed sand is cleaner with lower water demand.With the increase of the blending proportion of water-washed sand,the content of water reducing agent in concrete is decreasing,and the fluidity of concrete is improved.Under the condition of pumping construction technology,it is recommended that the blending proportion of water-washed sand to wind-sucked sand is 7/3.With the increase of the blending proportion of water-washed sand,the compressive strength of concrete increases gradually with a decreasing electric flux and improving carbonization resistance,which is mainly due to the increased blending proportion of water-washed sand improves the compactness of the concrete.The research work can promote the application of the concrete with machine-made sand and improve the quality thereof.