Influence of Fibre Treatment and Matrix Modification on Mechanical Properties of Flax Fibre Reinforced Mortars after Freeze/Thaw Cycles

Abstract:

The aim of this study was to examine the influence of flax fibre protection with the linseed oil and a matrix modification with cement substitution with metakaolin (in 10wt% and 15wt%) on the mechanical properties of cement-based mortars under severe environmental conditions of freeze/thaw cycles. Cement-based mortars (with the dimension of 40x40x160 mm³) were reinforced by 10mm long discrete flax fibres (Linum usitatissimum) and exposed to 51 freeze/thaw cycles under laboratory condition. Their compressive and flexural strengths, as well as specific energy absorption capacity were measured after freeze/thaw cycles and compared to the results of mortars cured for same time in water. Under freeze/thaw cycles mortars reinforced with linseed oil-treated fibres showed the same range of degradation of the compressive and flexural strengths, however, a more pronounced degradation of energy absorption capacity compared to non-treated fibre reinforced mortars was observed. The matrix modification, by partial cement substitution with metakaolin showed optimistic results under freeze/thaw cycles. The compressive strength when cement was partially substituted with metakaolin (in both dosages) increased whereas the flexural strength was slightly lower in case of 10wt% substitution and markedly lower under higher (15wt%) cement substitution. The most relevant is that the decrease of the energy absorption capacity of the fibre reinforced mortar was completely prevented when cement was substituted with metakaolin. It is shown that the energy absorption of the non-treated fibre reinforced mortars increases by 27% when cement was substituted with metakaolin (both 10wt% and 15wt%).

• Periodical: Construction Technologies and Architecture (Volume 1)
• Pages: 817-824
• DOI: https://doi.org/10.4028/www.scientific.net/CTA.1.817
• Online since: January 2022
• Authors: Bojan Poletanovic*, Katalin Kopecsko, Ildikó Merta
• Keywords: Fibre Treatment, Flax Fibers, Freeze/Thaw, Linseed Oil, Matrix Modification, Mechanical Properties, Metakaolin, Mortar

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