净水功能型透水混凝土的组成设计研究

为净化雨水和补充地下水,设计了一类净水功能型偏高岭土基地聚合物透水混凝土。通过研究壳聚糖掺量、碱激发剂模数与碱当量对偏高岭土基地聚合物浆体力学、吸附特性的影响,制备了一种可用于透水混凝土的高吸附性浆体材料。基于此,进一步探讨了透水混凝土骨料堆积孔隙率、浆集比(P/A)等体积结构参数对其净水、透水与力学性能的影响。结果表明:随着壳聚糖掺量的增加,偏高岭土基地聚合物的强度呈先提高后降低的趋势,Pb²⁺的吸附量呈增大趋势;随着骨料堆积孔隙率的增大,透水混凝土的力学和净水性能均减弱,透水性增强;随着浆集比的增大,透水混凝土力学与净水性能增大,透水性减小。最终设计出净水、透水与力学性能协调的透水混凝土,其28 d抗压强度、透水系数和Pb²⁺去除率分别为20.1 MPa、0.67 cm/s和90.5%。

Composition Design of Pervious Concrete with Water Purification Function

In order to purify rainwater and supplement groundwater, a class of metakaolin-based geopolymer pervious concrete with water purification function was designed. By studying the effects of chitosan content, alkali activator modulus and concentration of alkali activator on the mechanical and adsorption properties of the metakaolin-based geopolymer, a kind of paste material with high adsorption for pervious concrete was prepared. The effects of volume structure parameters such as bulk porosity of aggregate and P/A (paste aggregate ratio) on water purification, water permeability and mechanical properties of pervious concrete were studied. The results show that with the increase of chitosan content, the strength of metakaolin-based geopolymer increases firstly and then decreases, and the adsorption capacity of Pb²⁺ increases. With the increase of bulk porosity of aggregate, the mechanical and water purification properties of pervious concrete decrease, and the water permeability increases. With the increases of the P/A, the mechanical and water purification properties of pervious concrete increase, while the water permeability decreases. The 28 d compressive strength, permeability coefficient and Pb²⁺ removal rate of pervious concrete with coordinated water purification, permeability and mechanical properties are 20.1 MPa, 0.67 cm/s and 90.5%, respectively.