机制砂混凝土工作性调控技术研究

Study on Control Technology of Manufactured Sand Concrete Workability

机制砂和碎石的质量波动会影响机制砂混凝土的工作性。通过试验研究了机制砂亚甲蓝(MB)值和碎石含泥量对不同强度等级机制砂混凝土工作性的影响,并研究了相同工作性条件下机制砂混凝土工作性调控措施。结果表明:随机制砂MB值增大,且混凝土初始工作性变差,混凝土工作性损失增大,特别是对低强度等级的机制砂混凝土影响更大;碎石含泥量也会对机制砂混凝土的工作性产生较大的影响,因此需要严格限制碎石含泥量;当机制砂MB值较高时,碎石含泥量必须控制在较低水平,同时需要增加外加剂掺量,才能保证混凝土工作性满足要求。

Quality fluctuation of manufactured sand and crushed stone would influence the workability of manufactured sand concrete.The effect of MB value of manufactured sand and clay content of crushed stone on manufactured sand concrete workability was studied.The results show that with lager MB value,the initial and loss of concrete workability would be negatively affected,and the situation can be worse for low strength manufactured sand concrete.The clay content of crushed stone used in manufactured sand concrete production should be tightly restricted,since it would have negative effect on manufactured sand concrete workability.The control technology of manufactured sand concrete workability was further studied with the same workability requirement.It shows that,when the MB value of manufactured sand is large,the clay content of crushed stone should remain at low level,and the dosage of admixture should be increased to meet the requirement of concrete workability.