Synergetic effects of recycled crumb rubber and glass cullet on the engineering properties of geopolymer mortar. (March 2023)

• Record Type: Journal Article
• Authors: Deng, Ziming; Yang, Zhangfeng; Pan, Xinxiang
• Is Part Of: Cement & concrete composites. Volume 137(2023)
• Publication Date: 2023-03
• Subjects: Recycled crumb rubber -- Recycled glass cullet -- Geopolymer mortar -- Engineering properties -- Microstructure -- Eco-efficiency; 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.2022.104907
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: The large amounts of waste glass and tires arouse a great interest in the use of recycled crumb rubber (RCR) and glass cullet (RGC) as fine aggregates. However, there are currently few studies regarding the influences of the combined use of RCR and RGC on the performances of geopolymer mortar, and their synergetic effects are still unclear. To fill this gap, this study investigated the engineering properties, microstructure, and eco-efficiency of geopolymer mortar incorporating RCR and RGC, with the mix ratios of 10:0, 7:3, 5:5, 3:7, and 0:10. The results showed that the synergetic use of RCR and RGC counteracted their adverse effects. The incorporation of RGC increased the relatively low flowability, compressive, and splitting tensile strengths as well as reduced the drying shrinkage caused by RCR. On the other hand, the incorporation of RCR improved the fresh density, flexural strength, high-temperature resistance, sorptivity, and chloride resistance degraded by RGC. These different influences of RCR and RGC on the performances were attributed to their distinct characteristics, i.e., the significantly lower water absorption, softer nature, and rougher surface of RCR than those of RGC. Besides, the bridging effect of attached microfibers on RCR particles was beneficial to improve flexural strength and high-temperature resistance. In addition, the geopolymer mortar showed significantly lower embodied CO2 emissions and embodied energy than the conventional one. The mix ratio of 30% RCR and 70% RGC is most recommended for applications because the shortcomings of RCR and RGC were minimized concurrently in this mix ratio. Graphical abstract: Image 1 Highlights: RCR and RGC are used collaboratively as fine aggregates in geopolymer mortar. Fresh, mechanical properties and durability of the mortar are investigated. Phases, microstructure, and eco-efficiency of the mortar are investigated. Synergetic effects of RCR and RGC on the performances of the mortar are shown. Potential applications of eco-friendly mortar are proposed.