碎石含泥量对海工高性能混凝土性能影响试验研究

Investigated on effect of clay content in crushed stone on properties of high performance marine concrete

针对海工混凝土用碎石含泥量容易超标的问题,开展碎石含泥量亚甲基蓝曲线定量分析及含泥量对海工高性能混凝土性能影响规律的研究。试验结果表明:碎石含泥量包括黏土质泥粉和石粉,其中黏土质泥粉对海工混凝土性能的影响起主导作用。随着含泥量的增加,混凝土拌合物的工作性能逐渐变差,混凝土的抗压强度逐渐下降,干缩逐渐增大,混凝土的抗氯离子渗透性能和抗裂性能逐渐下降;含泥量超过1.5%时,相同工作性条件下外加剂掺量明显增大、抗压强度明显下降、干缩明显增加;含泥量超过1.0%时,混凝土抗氯离子渗透性和抗裂性明显下降;海工混凝土用碎石含泥量要求可适当放宽,合理范围应控制在1.0%以内。

In order to solve the problem that the clay content in crushed stone used for marine concrete was easy to exceed,quantitative analysis of methylene blue curve calibration of clay content and the effect of clay content on performance of marine concrete were investigated.The results showed that clay content in crushed stone included clayey mud powders and stone powders,and clayey mud powders had a dominant effect on the performance of marine concrete.With the increase of clay content in crushed stone,the workability of concrete gradually got worse,the compressive strength of concrete decreased gradually,dry shrinkage increased gradually,and chloride ion resisting property and crack resistance of concrete decreased gradually.Moreover,when the clay content was greater than 1.5%,the amount of admixture in concrete increased obviously under the condition of the same workability;compressive strength of concrete decreased obviously,and drying shrinkage increased significantly.Meanwhile,when the clay content was greater than 1.0%,chloride ion resisting property and crack resistance of concrete decreased significantly.In short,the requirement of clay content in crushed stone used for marine concrete should be relaxed,and the reasonable limits should be controlled within 1.0%.