Understanding and eliminating of expansion caused by recycled glass fiber reinforced plastic powder in concrete. (12th September 2022)

• Record Type: Journal Article
• Authors: Ma, Guowei; Zhou, Boyu; Zhang, Mo; Sanjayan, Jay
• Is Part Of: Construction & building materials. Volume 347(2022)
• Publication Date: 2022-09-12
• Subjects: Recycled GFRP powder -- Volumetric expansion -- Hydration kinetics -- Microstructure -- Porosity; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.128542
• Languages: English
• ISSNs: 0950-0618

Abstract

Graphical abstract: Highlights: Gas released by dissolution of rGP in cement resulted in expansion and strength loss. The ultrafine nature of rGP decreased the hydration degree and compactness of mortar. NaOH pre-soaking of rGP fully eliminated expansion and increased strength of mortar. Silica fume reduced expansion and improved compactness and strength of rGP mortar. Abstract: Applying crushed glass fiber reinforced plastic (GFRP) powder as fine aggregates in concrete provides a viable approach for waste GFRP recycle. However, expansion induced performance deterioration of concrete is a concern. The expansion mechanism and the effectiveness of five types of modification treatments were comprehensively investigated by testing the physical and mechanical properties, microstructure and hydration kinetics of recycled GFRP powder (rGP) filled mortar. The gas of H2, NH3 and CH4 produced by the reaction between rGP and alkaline pore solution was the main cause for the expansion. This expansion can be significantly reduced by adding silica fume and fully eliminated by presoaking rGP in NaOH solution. After modification, the compressive and flexural strength of rGP filled mortar were increased by 67% ∼ 100% and 25% ∼ 60%, respectively. The findings shed light on the potential application of rGP as additives in concretes with proper modification, such as expansion agent and foaming agent.