黑云母石英片岩机制砂的特性及混凝土配制研究

Study on Characteristic of Biotite Quartz Schist Manufactured Sand and Concrete Preparation

为探讨黑云母石英片岩机制砂用于混凝土的可行性,测试其理化性能,研究石粉含量对机制砂吸附性、需水量比和胶砂强度的影响,并将其与细河砂按不同比例掺配成混合砂用于C20,C30,C40混凝土的配制。结果表明,黑云母石英片岩机制砂的压碎指标、MB值和石粉含量等核心指标均不符合标准要求;机制砂MB值和需水量比随机制砂中石粉含量的增加而增大,胶砂强度在石粉含量超过3%后逐步降低;混合砂中机制砂所占比例越高,混凝土达到等工作性能所需减水剂掺量越高,强度越低,干缩越大;为配制C20,C30,C40混合砂混凝土,黑云母石英片岩机制砂在混合砂中所掺比例应分别不超过60%,50%,40%。

In order to explore the feasibility of biotite quartz schist(BQS)manufactured sand for preparing concrete,the physical and chemical properties of the manufactured sand were tested,the effects of stone powder content on the adsorption,water demand ratio and mortar strength of the manufactured sand were studied,and mixed with fine river sand in different proportions to form mixed sand for the preparation of C20,C30 and C40 concrete.The results show that the crushing index,MB value and stone powder content of the BQS manufactured sand do not meet the standard requirements.With the increase of stone powder content,the MB value of the manufactured sand and its water demand ratio increase,and the mortar strength gradually decreases when the stone powder content exceeds 3%.The higher the proportion of machine-made sand in the sand mix,the higher the amount of water reducing agent required to achieve the same working properties of concrete,the lower the strength and the greater the dry shrinkage.For preparing C20,C30 and C40 concretes,the proportion of the BQS manufactured sand in the mixed sand shall not exceed 60%,50%and 40%respectively.