PROPERTIES OF COATED AND UNCOATED BIOMASS AGGREGATES AND THEIR EFFECTS ON THE STRENGTH AND WATER PERMEABILITY OF PERVIOUS GEOPOLYMER CONCRETE

Abstract

Biomass aggregate (BA) is a by-product of biomass industries which is less dense and more porous
than natural aggregate. In this two-part study, BA was mixed with fly ash and alkaline liquid, and heated in an
oven at 80 °C for 24 h to produce coated biomass aggregate (CBA). The first part of this study was focused on
the density, specific gravity, Los Angeles test, water absorption, aggregate impact value, and aggregate
crushing value of BA, CBA, and normal aggregates (NA). The second part was focused on compressive
strength and water permeability of pervious geopolymer concrete (PGC) that was produced with BA and CBA.
Pervious concrete is a non-slip porous pavement concrete that allows water to slip through. In this study PGC
was prepared from alkaline solution: fly ash ratio of 0:5, fly ash/coarse aggregate ratio of 1:7, Na2SiO3/NaOH
ratio of 2:5, and NaOH concentration of 10 molarity. PGC was cured at 80°C for 24 h. PGC made with CBA
had higher compressive strength without much effect on water permeability. It has been found that PGC made
with BA and CBA had lower density than PGC made with NA. Results indicated that both BA and CBA are
viable alternative aggregates for producing PGC.