Ma Quan, Yang Wei, Duan Zhenhua, Liu Hui, Hua Minqi, Deng Qi
Department of Structural Engineering, Tongji University, Shanghai 200092, China.
Department of Civil Engineering, Changzhou University, Changzhou 213164, China.
Materials (Basel). 2022 Nov 24;15(23):8368. doi: 10.3390/ma15238368.
Geopolymer-recycled pervious concrete (GRPC) is a novel concrete that can effectively inhibit the corrosion of acid rain and alleviate urban waterlog. The goal of this study is to ascertain the optimal pore size of GRPC and study its acid rain resistance activated by different alkali-activators. Three different sizes (0.8, 1.0, and 1.2 mm) were separately chosen as the pore diameters of GRPC. The alkali-activator solution adopted sodium hydroxide (NaOH), sodium silicate (NaSiO), and a mixture of the two. The mechanical properties and permeability coefficient were tested to determine the optimal pore size of GRPC. After that, specimens with the optimal pore size were immersed in a simulative acid rain solution (sulfuric acid solution with pH = 4.0) for 6 d and were dried 1 d until 56 d. The effects of different alkali activators on acid rain resistance of GRPC were analyzed by compressive strength, neutralization depth, and mass loss. The results manifested that the mechanical properties of GRPC were excellent, the compressive strength of GRPC reached more than 60.1 MPa, and their splitting tensile strength attained more than 5.9 MPa, meeting the strength requirement of the road for heavy traffic load. Considering the mechanical properties and the acid rain purification effect of alkaline GRPC required a relatively small permeability coefficient; the optimal pore size was 1 mm. When specimens with optimal pore size were exposed to acid solution, the corrosion products (gypsums) would block the pores of GRPC to inhibit further corrosion, keeping the stability of the compressive strength. GRPC activated by the mixture of NaOH and NaSiO generated a more stable amorphous three-dimensional network structure, endowing GRPC with better mechanical properties and acid corrosion resistance.
地质聚合物再生透水混凝土（GRPC）是一种新型混凝土，能够有效抑制酸雨侵蚀并缓解城市内涝。本研究的目的是确定GRPC的最佳孔径，并研究不同碱激发剂对其酸雨抗性的影响。分别选取三种不同尺寸（0.8、1.0和1.2毫米）作为GRPC的孔径。碱激发剂溶液采用氢氧化钠（NaOH）、硅酸钠（NaSiO）以及二者的混合物。通过测试力学性能和渗透系数来确定GRPC的最佳孔径。之后，将具有最佳孔径的试件浸泡在模拟酸雨溶液（pH = 4.0的硫酸溶液）中6天，然后干燥1天，直至56天。通过抗压强度、中和深度和质量损失分析不同碱激发剂对GRPC酸雨抗性的影响。结果表明，GRPC的力学性能优异，其抗压强度达到60.1 MPa以上，劈裂抗拉强度达到5.9 MPa以上，满足重交通荷载道路的强度要求。考虑到碱性GRPC的力学性能和酸雨净化效果需要相对较小的渗透系数，最佳孔径为1毫米。当具有最佳孔径的试件暴露于酸性溶液时，腐蚀产物（石膏）会堵塞GRPC的孔隙以抑制进一步腐蚀，保持抗压强度的稳定性。由NaOH和NaSiO混合物激发的GRPC生成了更稳定的无定形三维网络结构，赋予GRPC更好的力学性能和耐酸腐蚀性。
