Effect of freeze-thaw cycles on the mechanical behavior of geopolymer concrete and Portland cement concrete containing micro-encapsulated phase change materials. (10th March 2019)

• Record Type: Journal Article
• Authors: Pilehvar, Shima; Szczotok, Anna M.; Rodríguez, Juan Francisco; Valentini, Luca; Lanzón, Marcos; Pamies, Ramón; Kjøniksen, Anna-Lena
• Is Part Of: Construction & building materials. Volume 200(2019)
• Page Start: 94
• Page End: 103
• Publication Date: 2019-03-10
• Subjects: Geopolymer concrete -- Portland cement concrete -- Micro-encapsulated phase change materials -- Freeze-thaw cycles -- Compressive strength -- Setting times -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2018.12.057
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Addition of micro-encapsulated phase change materials to concrete reduce the adverse effect of freeze-thaw cycles. Geopolymer concrete maintains the compressive strength better after freeze-thaw cycles than Portland cement concrete. The setting times of geopolymer paste becomes much faster when the temperature is decreased from 20 to 0 °C. Microcracks is observed in the concrete structure after the freeze-thaw cycles. Abstract: The effect of frost conditions on the physical and mechanical properties of geopolymer concrete (GPC) and Portland cement concrete (PCC) containing two different micro-encapsulated phase change materials (MPCM) was examined. Microstructural studies revealed that the freeze-thaw induced concrete deterioration can be contributed to microcracks appearing at the weak interfacial transition zones between paste/aggregate and paste/MPCM. The addition of MPCM provided an excellent resistance against freeze-thaw cycles with minor reduction of the compressive strength, unlike the samples without MPCM where a stronger reduction was observed. When the temperature was reduced to 0 °C, the initial setting time of Portland cement pastes became longer due to the low temperature and the high viscosity. For geopolymer pastes, the initial setting time became shorter due to phase separation of the alkaline solution at low temperatures. Increasing the MPCM concentration reduced the final setting time for both Portland cement and geopolymer pastes.