Investigating the effect of elevated temperatures on the properties of mortar produced with volcanic ash

Abstract

During the recent years, the use of pozzolanic materials (e.g. volcanic ash) in concrete and cement manufacturing has increased significantly since it can reduce the environment hazard associated with using Portland cement. In this paper, the effect of elevated temperatures on the physical and mechanical characteristics of building mortar produced with volcanic ash is experimentally explored. In order to evaluate the performance of the mortar, four different proportions of volcanic ash (0, 5, 15 and 25%)-as weight replacement of the cement-were prepared. A series of tests were conducted after 28, 90 and 120 days under different temperatures (25, 200, 500 and 800Cº). This paper demonstrates that the replacement of cement by a proportion of volcanic ash can sustain an acceptable level of compressive strength and improve the overall characterization of the mortar while reducing the amount of CO2 released. The mortar with 15% ratio of the volcanic ash replacement showed better flexural and the tensile strength. This paper also heights that the volcanic ash replacement affects the late-age properties of the mortar more than the early-age ones at both ambient and elevated temperatures.

Mechanical Performance of High-Strength Sustainable Concrete under Fire Incorporating Locally Available Volcanic Ash in Central Harrat Rahat, Saudi Arabia

“…A comparison of current experimental data with the results of linear regression by Awal and Shehu for control concrete [62] and power regression by Saha et al [58] is presented in Figure 11. Although, Awal and Shehu proposed different linear regressions (for control and palm oil fuel ash concretes) according to the exposure of 100 mm cube specimens up to 800 • C, their proposed regression for control concrete only reasonably predicts the residual strength of concrete for high exposure temperatures between 600 and 800 • C, while it underestimates the residual strength for exposure between 200 and 600 • C. The possible reason for this underestimated RCS can be due to the different geometry of their tested specimens (cubes), different heating regimes (exposure to peak temperature for 1 h only), and concrete of relatively lower strength (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) as compared to the current study (68-73 MPa). The power regression proposed by Saha et al was based on exposure of cylindrical specimens (100 mm × 200 mm) of ferronickel and FA concrete up to 800 • C. However, unlike Awal and Shehu, their prediction equation overestimated residual strength of concrete.…”

“…Demirel and Kelestemur [27] exposed a concrete blended with a binary mixture of finely ground pumice (FGP) and SF to high temperatures. They concluded that the addition of both FGP and SF decreased the compressive strength and reduced the unit weight of concrete at a temperature above 600 • C. Mohamad et al [28] experimentally explored the performance of VA in cement mortar and they highlighted that the replacement of cement with VA affects the properties of mortar at a later age at both ambient and high temperatures. The addition of VA up to 20% in the HSC exhibited better resistance to chloride penetrability and deterioration along with an enhancement in the residual strength subjected to a high temperature of about 800 • C. However, reduced durability and loss of strength were noticeable when the temperature increased beyond 800 • C [29].…”

Using High Reactivity Attapulgite for Stabilizing Collapsible Gypseous Soil

“…Single consolidation test was carried out using an oedometer cell and following the procedures indicated by Mohamed et al [23], and Jennings and Knight [24] to determine the collapse potential of the samples. The sample in this test is loaded in a dry state without any water according to the standard consolidation test.…”

Experimental Study on the Effect of Basalt Fiber and Sodium Alginate in Polymer Concrete Exposed to Elevated Temperature

“…Three different temperature ranges are generally used in concrete studies that include low temperature (<0 • C), medium temperature (0-50 • C), and high or elevated temperature (<50 • C). The thermal response of concrete to elevated temperature mainly depends on constituents' characteristics and the mix composition [38]. Based on the applications and intended exposure condition, previous researches have considered various temperature ranges to evaluate the thermal response of concrete which can be classified as temperatures below 200 • C [39][40][41], below 600 • C [42][43][44], and below 1000 • C [45][46][47].…”