As lightweight concrete is now increasingly used in medium
and high-rise buildings worldwide including Thailand, the development
of sustainable lightweight construction material using
WTS as an aggregate is the focus of this paper. Natural soil has been
successfully used as an aggregate to develop a lightweight cellular
material using Portland cement as a cementing agent [37–41]. The
development of lightweight cellular material using WTS as an
aggregate and geopolymer as a cementing agent has however not
been previously investigated. This developed sustainable lightweight
material is herein designated as ‘‘Water Treatment
Sludge-Fly Ash Lightweight Cellular Geopolymer, WTS–FA LCG’’.
The primary material properties; i.e., unit weight and strength
at various influential factors of the WTS–FA LCG are investigated
and presented in this paper. The air foam is used to reduce the unit
weight of WTS–FA LCG. The influential factors investigated include
air content (Ac), Na2SiO3/NaOH ratio, liquid alkaline activator content
(L), heat duration and curing time. Scanning electron microscopy
(SEM) analysis is further undertaken to investigate the role
of influential factors on unit weight and strength. This research will
enable WTS traditionally destined for landfill to be used in a sustainable
manner as an aggregate in WTS–FA LCG, which is signifi-
cant from engineering, economical and environmental
perspectives