Influence of silica fume, metakaolin & SBR latex on strength and durability performance of pervious concrete

This study evaluates the performance of pervious concrete subjected to rapid freeze-thaw (F-T) cycling, calcium leaching and the combined attack of calcium leaching and F-T cycling. Silica fume, metakaolin and SBR polymer emulsion were incorporated at different levels into pervious concrete mixes to improve strength and durability performances. The results indicated that the addition of 5% fine sand and proper compaction had a positive influence on improving the resistance of pervious concrete to F-T cycling. The increase of supplementary cementitious materials (SCMs) from 5% to 10% significantly improved the resistance to rapid F-T cycling and to the combined attack of calcium leaching and F-T cycling. The optimum content of SCMs was 10% based on the mechanical and durability performance of pervious concrete with acceptable permeability. Calcium leaching in 6 M NH4NO3 solution combined with F-T cycling induced severe surface deterioration and internal damage compared to individual attacks of F-T cycling or leaching. Compared with control and polymer-modified mixes, pervious concrete incorporated SCMs possessed better resistance of calcium leaching and frost. The morphological changes caused by calcium leaching exhibits the decreased volume fraction of solid phases in a cement matrix and consequently increased the porosity, which ultimately degraded strength and durability performance of pervious concrete. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study evaluates the performance of pervious concrete under rapid freeze-thaw cycling, calcium leaching, and their combined attack. The addition of fine sand and proper compaction can improve the resistance to freeze-thaw cycling. Increasing the supplementary cementitious materials (SCMs) content from 5% to 10% significantly enhances resistance, with 10% being the optimal content.