Effects of Composite Admixtures on Mechanical Properties and Permeability Coefficient of Binder Paste and Porous Pervious Concrete Authors and Affiliations
1 Faculty of Architecture and Urban planning, Chongqing University, Chongqing 400030, China;
Aiming at the engineering bottleneck that it is difficult to balance strength and water permeability of pervious concrete, this paper investigates the effects of single and compound incorporation of triethanolamine and magnesium fluorosilicate on mechanical properties, pore structure and permeability coefficient of cement binder paste and porous pervious concrete. The experimental results indicate that triethanolamine presents an obvious characteristic of remarkable early-strength improvement but insufficient later strength gain, while magnesium fluorosilicate can steadily and continuously enhance the strength. The combined admixture system exhibits excellent synergistic effect. The retarding regulation of MF effectively mitigates the deficiency in later-age strength development of TEA-amended systems caused by excessively rapid early hydration, and significantly optimizes the homogeneity of microstructure at later ages. The 28d compressive strength of paste in group T5M6 (0.5wt%TEA、0.6wt%MF) reaches as high as 114.5MPa. When applied in pervious concrete, the modified paste acts as a high-performance "bonding bridge" to strengthens the bond at aggregate contact points. For groups M9 (0.9wt%MF) and T5M6, the 28d compressive strength reaches 26.8MPa and approximately 29.0MPa respectively while maintaining a high permeability coefficient, which effectively breaks the trade-off between strength and water permeability. The research results can provide theoretical support for the preparation of high-performance pervious pavement materials for sponge cities.
Effects of Composite Admixtures on Mechanical Properties and Permeability Coefficient of Binder Paste and Porous Pervious Concrete Authors and Affiliations