Properties of metakaolin-based green pervious concrete cured in cold and normal weather conditions

Owing to structural and environmental reasons, the use of pozzolans as cementitious materials in several kinds of concrete has increased in the last decade. The objectives of this experimental study were to examine the effect of weather conditions, winter and spring, on curing metakaolin-based pervious concrete; investigate the impact of various eco-friendly fine aggregates for improving the structural behaviour of this type of concrete in the above conditions; study the performance of these mixtures in the management of urban runoff; and evaluate the influence of three fine aggregates (quartz, dolomite and vermiculite) on improving the structural behaviour of various metakaolin-based pervious concrete mixtures (metakaolin was replaced by 5-25% for cement). Results indicated that: (1) in the mixtures which were cured in winter, metakaolin had no positive effect on performance of pervious concrete, but it intensified the freeze trend, so that the compressive strength of pervious concrete was significantly reduced by increasing the proportion of metakaolin, (2) in the samples cured in spring, metakaolin led to a 15% increase in the compressive strength of pervious concrete compared to the control sample, (3) the fine aggregates had desirable effects on improving the structural behaviour of pervious concrete; they reduced the freeze severity in the mixtures cured in winter and increased the compressive strength of mixtures cured in spring and (4) all the tested mixtures were able to drain 10-40 cm of runoff in a short time period.