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<p>Concrete in harsh environments faces significant durability risks, mainly from external sulfate attack. This study investigates the impact of seasonal variations in temperature and humidity on ESA by comparing the performance of samples containing ordinary Portland cement (O) and modified mix containing silica fume and GGBFS (SG). These samples were exposed to 10% Na<sub>2</sub>SO<sub>4</sub> solution under three distinct exposure conditions that simulate seasonal change: high temperature (50&#xa0;°C) complete immersion; high humidity (22&#xa0;°C) and moisture flux (50&#xa0;°C) through partial immersion; and wet-dry cycles (Wet at 22&#xa0;°C- Dry at 50&#xa0;°C). A multi-faceted analysis reveals that SG sample under high temperature has the most detrimental effect on accelerating sulfate attack, including mass (− 1.5%) and volume (+ 4.5%) change, compressive (− 2.2%) and flexural (+ 3%) strength, ultrasound pulse velocity (− 2.1%), and elastic dynamic modulus (+ 1%). Microscopic analysis shows the presence of ettringite, gypsum and physical attack through crystallization of mirabilite in the middle portion, under high humidity conditions. The high moisture flux at high temperature showed the presence of ettringite in the evaporation interface zone and gypsum. The wet-dry cycles introduce a dual degradation mechanism—chemical degradation and physical attack through the crystallization of thenardite. While the modified mix consistently demonstrated superior resistance to sulfate ingress under high humidity, they were vulnerable to the accelerated degradation caused by high temperatures. Statistical correlation was performed to understand the inter-relation between parameters and regression was done to establish a connection between destructive and non-destructive tests.</p>

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Concrete Durability in Arid Region: Influence of Seasonal Temperature and Humidity Variation on Sulfate Attack on Modified Cement Mortar

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年4月29日

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  • Mohsina M. Sherief,
  • Remilekun A. Shittu,
  • Fatima I. Alhamadi,
  • Ahmed Alkaabi,
  • Akram Alfantazi

摘要

Concrete in harsh environments faces significant durability risks, mainly from external sulfate attack. This study investigates the impact of seasonal variations in temperature and humidity on ESA by comparing the performance of samples containing ordinary Portland cement (O) and modified mix containing silica fume and GGBFS (SG). These samples were exposed to 10% Na2SO4 solution under three distinct exposure conditions that simulate seasonal change: high temperature (50 °C) complete immersion; high humidity (22 °C) and moisture flux (50 °C) through partial immersion; and wet-dry cycles (Wet at 22 °C- Dry at 50 °C). A multi-faceted analysis reveals that SG sample under high temperature has the most detrimental effect on accelerating sulfate attack, including mass (− 1.5%) and volume (+ 4.5%) change, compressive (− 2.2%) and flexural (+ 3%) strength, ultrasound pulse velocity (− 2.1%), and elastic dynamic modulus (+ 1%). Microscopic analysis shows the presence of ettringite, gypsum and physical attack through crystallization of mirabilite in the middle portion, under high humidity conditions. The high moisture flux at high temperature showed the presence of ettringite in the evaporation interface zone and gypsum. The wet-dry cycles introduce a dual degradation mechanism—chemical degradation and physical attack through the crystallization of thenardite. While the modified mix consistently demonstrated superior resistance to sulfate ingress under high humidity, they were vulnerable to the accelerated degradation caused by high temperatures. Statistical correlation was performed to understand the inter-relation between parameters and regression was done to establish a connection between destructive and non-destructive tests.