A preliminary investigation into the use of alkali-activated blast furnace slag mortars for high-performance pervious concrete pavements

Pervious concrete (PC) pavements are water control systems for infiltrating storm water, reducing runoffs, contrasting heat-island effects and noise diffusion in urban environments. Their poor strength and stiffness, which stem from their porosity, limit their application for use in sidewalks and residential streets. To overcome this limitation, the research aimed at developing an alkali-activated blast furnace slag binder (AA-BFS) which, when added to the concrete mixture, would enable it to attain the characteristics required for application in trafficked road pavements. A Portland cement (CEM-I) and a blast furnace cement (CEM-III/C) were included for comparison purposes. Standard and high-performance pervious concrete (HPPC) mortars were tested with the same mix ratio of binder, sand, and admixtures. The effects of a latex polymer admixture were also analysed. After 2, 7, and 28 days of curing, AA-BFS mortars exhibited the greatest flexural and compressive strengths. As expected, CEM-III/C needed more time to achieve strengths comparable to those recorded for CEM-I. The addition of latex failed to result in any discernible benefits in terms of the stress-strain behaviour of mortars. The results confirm that AA-BFS is a sustainable option for HPPC production.