饱和泥浆法透水混凝土抗堵性试验研究

以表观填隙系数为主要控制指标制备了不同强度等级的透水混凝土,分析了透水指标与连通孔隙率的关系。采用黄泛区粉土饱和泥浆作为堵塞介质,测定了预定次数堵塞(淋泥-晾干)循环后的各项透水指标,评价了饱和泥浆对透水混凝土抗堵塞性能的影响。结果表明:透水混凝土各项透水指标与连通孔隙率密切相关;当体系水灰(胶)比为0.24、表观填隙系数为0.70、高性能减水剂掺量适当时,透水混凝土抗压强度达到最高(28.3 MPa)且不积浆;经过堵塞循环后,透水混凝土的透水性下降明显,与掺减水剂试样相比,未掺减水剂试样的透水性损失速度快;初始连通孔隙率为10.5%的透水混凝土,经受近30次饱和泥浆的堵塞循环后,透水系数基本衰减到相关规程规定的下限值以下。

Experimental Study on Resistance to Clogging of Pervious Concrete by Saturated Slurry Method

The samples were prepared by controlling apparent paste-void ratio in pervious concrete,and the relation of permeable parameters to continuous porosity was analyzed.The saturated slurry made of silt in Yellow River Flood Area played a role of clogging medium.The permeable parameters were measured after the samples suffered scheduled clogging(slurry sprinkling-air drying)cycles to evaluate the effect of saturated slurry on resistance of pervious concrete to clogging.The results reveal that the permeable parameters of pervious concrete are closely related to its continuous porosity.The pervious concrete with the highest strength(28.3 MPa)and without paste flow can be prepared with water-cement(binder)ratio of 0.24,proper dosage of superplasticizer and in apparent paste-void ratio of approximate 0.70.The permeability of pervious concrete obviously reduces after clogging cycles.The permeability of pervious concrete samples without superplasticizer generally loses faster than that of samples with superplasticizer.For the pervious concrete with initial continuous porosity of 10.5%,its coefficient of permeability decreases to less than minimum value defined by related specification after nearly 30 clogging cycles.