Effect of Low and High Temperature on the Compressive Strength and Durability of Cement Mortar

Abstract

This study investigated the effect of low and high temperature on the compressive strength and durability of cement mortar. The aim was to determine how extreme temperature conditions affect the performance of mortar used in building construction in Northern Nigeria. A total of 60 mortar cubes of 50mm x 50mm x 50mm were cast using mix ratio 1:3 (cement:sand) with water-cement ratio of 0.5. The samples were cured for 28 days and then subjected to different temperature regimes: low temperatures of 5°C, 0°C, -5°C and high temperatures of 100°C, 300°C, 500°C and 700°C. Compressive strength test, weight loss test and visual inspection were conducted. Results showed that low temperature (5°C to -5°C) retarded hydration process and reduced compressive strength by 15-28% compared to control at 25°C. High temperature up to 100°C slightly increased strength by 5% due to accelerated hydration, but temperatures above 300°C caused significant reduction in strength. At 500°C and 700°C, strength reduction of 45% and 72% respectively was recorded, with severe cracking, spalling and colour change. The study concluded that both low and high temperatures have negative effects on cement mortar, with high temperature above 300°C being more destructive. It was recommended that during harmattan cold in Kano (5-10°C), concreting should be done in afternoon and use of warm water, and structures should be protected from fire.