Abstract
In the current study, elevated heat resistance of the mortars including 15% fly ash, ground granulated blast furnace slag and silica fume is investigated. Fly ash, ground granulated blast furnace slag and silica fume are replaced with cement past by weight in the prepared mortar samples. The prepared samples are kept in a furnace for 2 hours at 400 °C and 800 °C to find out effect of elevated temperature on compressive strength of the mortars. Compressive strength before and after heat exposure are measured in terms of evaluating elevated heat resistance. Control sample that does not contain any admixture, mortar including fly ash, mortar including ground granulated blast furnace slag and mortar including silica fume has 30.81 MPa, 33.62 MPa, 43.91 MPa and 51.83 MPa compressive strength before heat exposure, respectively. Compressive strength of the same samples after 400 °C and 800 °C heat exposure are 25.64 MPa and 8.12 MPa, 28.91 MPa and 11.56 MPa, 34.37 MPa and 15.21 MPa and 39.78 MPa and 21.85 MPa, respectively. The alteration of heat resistance of the mortars with fly ash, ground granulated blast furnace slag and silica fume is attributed to puzzoulanic behavior of the used materials. These materials react with Ca(OH)2 in cement and produce extra tobermorite gel (CSH phase) that provides extra durability to the composite.
Highlights
Cement is one of the most commonly used construction materials in all over the world (Çağlar et al, 2020)
Flexural tensile strength, compressive strength and elevated temperature resistance of mortar samples including 15 % ground granulated blast furnace slag (GGBFS), fly ash (FA) and silica fume (SF) as a partial replacement of ordinary Portland cement (OPC) are presented of the paper
Mortar samples with FA, GGBFS and SF are kept in a furnace for two hours at 400 C and 800 C to evaluate elevated heat resistance of the mortars
Summary
Cement is one of the most commonly used construction materials in all over the world (Çağlar et al, 2020). Exposure of high temperature causes damages in the cement-based structures. Cementitious composites might be subjected to elevated temperatures that damage the structural properties of materials (Zhou et al, 2020). In most cases high temperature causes deteriorations in the material due to physical and chemical changes that occur in cementitious composites. Akbar and Liew (2020) investigated effect of recycled carbon fiber on microstructure and mechanical properties of cement-based composites at elevated temperature. Qu et al (2020) studied elevated temperature resistance of alkali activated ground granulated blast furnace slag (GGBFS) and fly ash based geopolymer mortars. Physical and mechanical properties of mortars containing GGBFS, fly ash (FA) and silica fume (SF) as replacement of ordinary Portland cement (OPC) at elevated temperature are investigated. The objective of this study is to reveal mechanical and physical properties of mortar including the most available and used puzzolanic admixtures by exposing 400-800 °C heat for 2-hour time duration
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