Experimental Investigation of the TRM-to-Masonry Bond after Exposure to Elevated Temperatures: Cementitious and Alkali-Activated Matrices of Various Densities

Limited research has focused on the effect of high temperatures on the textile-reinforced mortar (TRM)-to-masonry bond. In this study, masonry prisms that were furnished with double-layered TRM strips were tested under shear bond conditions after their exposure to 200 °C and 400 °C for 1 h using the single-lap/single-prism setup. A total of four TRM systems were applied sharing the same type of textile –a dry AR glass fiber one– and different matrices: two cementitious matrices, namely a normal-weight (TRCNM) and a lightweight (TRCLM) one, and two counterpart alkali-activated matrices (TRAANM and TRAALM) based on metakaolin and fly ash. Specimens’ exposure to elevated temperatures did not alter their failure mode which was due to the sleeve fibers’ rupture along with core fibers’ slippage from the mortar. The residual bond capacity of the TRM systems decreases almost linearly with increasing exposure temperature. The alkali-activated textile reinforced mortars outperformed their cement-based counterparts in terms of bond strength at every temperature. All systems retained close to 50% of their original shear bond strength after heating at 400 °C. Per the type of binder, lightweight matrices resulted in either comparable (cement-based systems) or better (alkali-activated systems) heat protection at the TRM/masonry interface.

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Effect of Elevated Temperature on Mechanical Properties of High-Volume Fly Ash-Based Geopolymer Concrete, Mortar and Paste Cured at Room Temperature

Polymers ◽

10.3390/polym13091473 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1473

Author(s):

Jun Zhao ◽

Kang Wang ◽

Shuaibin Wang ◽

Zike Wang ◽

Zhaohui Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Elevated Temperature ◽

Fly Ash ◽

Residual Strength ◽

Elevated Temperatures ◽

High Volume ◽

Sem Analysis ◽

Geopolymer Concrete ◽

Ordinary Concrete ◽

Exposure Temperature

This paper presents results from experimental work on mechanical properties of geopolymer concrete, mortar and paste prepared using fly ash and blended slag. Compressive strength, splitting tensile strength and flexural strength tests were conducted on large sets of geopolymer and ordinary concrete, mortar and paste after exposure to elevated temperatures. From Thermogravimetric analyzer (TGA), X-ray diffraction (XRD), Scanning electron microscope (SEM) test results, the geopolymer exhibits excellent resistance to elevated temperature. Compressive strengths of C30, C40 and C50 geopolymer concrete, mortar and paste show incremental improvement then followed by a gradual reduction, and finally reach a relatively consistent value with an increase in exposure temperature. The higher slag content in the geopolymer reduces residual strength and the lower exposure temperature corresponding to peak residual strength. Resistance to elevated temperature of C40 geopolymer concrete, mortar and paste is better than that of ordinary concrete, mortar and paste at the same grade. XRD, TGA and SEM analysis suggests that the heat resistance of C–S–H produced using slag is lower than that of sulphoaluminate gel (quartz and mullite, etc.) produced using fly ash. This facilitates degradation of C30, C40 and C50 geopolymer after exposure to elevated temperatures.

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Bond strength performance of ceramic, fly ash and GBFS ternary wastes combined alkali-activated mortars exposed to aggressive environments

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.119088 ◽

2020 ◽

Vol 251 ◽

pp. 119088 ◽

Cited By ~ 2

Author(s):

Kwok Wei Shah ◽

Ghasan Fahim Huseien

Keyword(s):

Fly Ash ◽

Bond Strength ◽

Strength Performance ◽

Alkali Activated

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EFFECT OF MIXING PROPORTION ON COMPRESSIVE STRENGTH OF FLY-ASH BASED GEOPOLYMER PASTE AND MORTAR USING TAGUCHI’S METHOD

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2015.72 ◽

2015 ◽

Vol 2 (1) ◽

Author(s):

Sajid Khan Afridi ◽

Vanissorn Vimonsatit

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Elevated Temperatures ◽

Three Dimensional ◽

Silica Content ◽

Polymeric Chain ◽

Low Carbon ◽

Solid Ratio ◽

Mix Proportion ◽

Alkali Activated

Alkali activated pozzolan are known low carbon cementitious binders which can be used to replace cement. The material is also known as geopolymer because of its three dimensional polymeric chain and ring like structure consisting silica and alumina. A common type of pozzolan used is fly ash because of its rich silica content; therefore the term alkali activated fly-ash based binders is adopted. Despite much research and development of this material, there is no specific standard for design mix proportion. This research used the Taguchi’s design of experiment method to determine the optimum mix proportion of alkali activated fly ash based cement paste and mortar. Four factors were considered in the tests, silica fume, sand to cementitious ratio, liquid to solid ratio, and percentage of superplasticiser. Tests were conducted on the 9 batches of alkali activated fly-ash based paste and mortar samples to determine the compressive strength under ambient condition. Tests were also conducted to determine the residual strength of the samples after exposed to elevated temperatures. ANOVA analysis of the test results revealed the main factors contribution on the tested properties and led to the determination of the optimum design proportion of the factors considered in these tests.

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Influence of slag content on the bond strength, chloride penetration resistance, and interface phase evolution of concrete repaired with alkali activated slag/fly ash

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.120639 ◽

2020 ◽

Vol 263 ◽

pp. 120639

Author(s):

Jingchong Fan ◽

Hongguang Zhu ◽

Jing Shi ◽

Zonghui Li ◽

Sen Yang

Keyword(s):

Fly Ash ◽

Bond Strength ◽

Phase Evolution ◽

Penetration Resistance ◽

Chloride Penetration ◽

Alkali Activated Slag ◽

Interface Phase ◽

Chloride Penetration Resistance ◽

Activated Slag ◽

Alkali Activated

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Bond Behavior between Steel Rebar and RCA Concrete after Exposure to Elevated Temperatures

Advances in Materials Science and Engineering ◽

10.1155/2020/5230295 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Wanjie Zou ◽

Jiongfeng Liang ◽

Dawei Liu ◽

Guangwu Zhang

Keyword(s):

Bond Strength ◽

Elevated Temperatures ◽

Coarse Aggregate ◽

Test Results ◽

Modified Model ◽

Bond Slip ◽

Bond Behavior ◽

Steel Rebar ◽

Exposure Temperature ◽

Increasing Temperature

To explore the bond behavior between steel rebar and recycled coarse aggregate (RCA) concrete after exposure to elevated temperatures, an experimental study was carried out. The results demonstrated that the bond strength of RCA concrete pullout specimens decreased greatly with increasing temperature. As the exposure temperature elevated, the slope of the ascending portion of the bond-slip curves gradually declined, and the descending portion of the curves tended to flatten. A modified model was developed to predict the bond strength between RCA concrete and steel rebar after exposure to elevated temperature, and the predicted results showed a very good fit in the experimental test results. Besides, the proposed bond-slip relations for steel rebar in RCA concrete after elevated temperatures showed satisfactory agreement with test results.

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