Alkali-activated fly ash foams for narrow-trench reinstatement. (May 2021)

• Record Type: Journal Article
• Authors: Rezaei, Mohammad; Bindiganavile, Vivek
• Is Part Of: Cement & concrete composites. Volume 119(2021)
• Publication Date: 2021-05
• Subjects: Narrow-trenching -- Alkali-activation -- Cementitious foams -- Fly ash -- Compressive strength -- Shrinkage -- Coefficient of thermal expansion -- Bond strength -- Asphalt concrete; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2021.103966
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Unlike with traditional earthfill, materials used in the reinstatement of narrow-trenching must satisfy certain engineering properties. Otherwise, the ongoing traffic and environ- mental condition will damage the trench, degrade the road pavement and damage the service-lines that were installed. This report identifies eight mixtures using Fly Ash as the alumino-silicate precursor to prepare alkali-activated foams, cast to densities between 600 and 1100 kg/m 3 . These systems were examined for their mechanical performance, dimensional stability, and bond with the asphalt substrate. The hardened foams were first tested for their strength, modulus of elasticity, and Poisson's ratio. This was followed by evaluating their drying shrinkage and their coefficient of thermal expansion. Lastly, these mixtures were cast against asphalt concrete to assess both slant shear and flexural bond strength. The test outcomes were used to rank the mixtures with an analytical hierarchy process. The results show that the mixtures at the median density (800 kg/m 3 ) offer the most promise and substantial benefit accrues from fibre reinforcement.