Influence of Sulfate Ions on Chloride Attack in Concrete Mortars Containing Silica Fume and Jajrood Trass
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RESEARCH PAPER
Influence of Sulfate Ions on Chloride Attack in Concrete Mortars Containing Silica Fume and Jajrood Trass Ali Akbar Ramezanianpour1 · Erfan Riahi Dehkordi2 · Amir Mohammad Ramezanianpour3 Received: 17 February 2017 / Accepted: 17 June 2020 © Shiraz University 2020
Abstract The effect of sulfate ions on chloride penetration has not been investigated in detail. In this research, standard ordinary portland cement (OPC) mortar and partial cement replacement by silica fume (7.5%) and trass a natural pozzolan (17.5%) were used to investigate the effect of sulfate ions on chloride attack. After 28 days of moist curing, specimens were subjected to chloride–sulfate solutions for 60, 120 and 180 days. According to the results after 208 days, the sulfate intermediate leads to decreased chloride attack in the control and a slight increase in silica fume samples. Regarding the trass sample, an intermediate state occurred. Silica fume reduces chloride penetration significantly. Trass samples generally show better performance than the control in this respect. Rapid chloride migration test (RCMT) was used to determine a method to evaluate the samples behavior in combined chloride–sulfate solutions, quickly. According to the results, RCMT was not an appropriate test to determine chloride penetration in combined chloride–sulfate solutions. Keywords Chloride · Sulfate · Combined effect · Concrete durability · Corrosion · Pozzolan
1 Introduction It is commonly accepted that chloride/sulfate destruction is the most serious problem for the service life of concrete structures especially in marine environments (Lee et al. 2008). Therefore, it is necessary to study the combined effect of these two phenomena. Al-Amoudi and Abdu-Al (1995) investigated the effect of sulfate and sulfate–chloride solutions on mortar expansion and strength reduction. Results show that chloride ions mitigate the sulfate attack * Erfan Riahi Dehkordi [email protected] Ali Akbar Ramezanianpour [email protected] Amir Mohammad Ramezanianpour [email protected] 1
Concrete Technology and Durability Research Center (CTDRc), Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
2
Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
3
Faculty of Civil Engineering, University of Tehran, Tehran, Iran
in ordinary portland cement (OPC)/SCMs. Sotiriadis et al. (2012) observed that limestone cement concretes have better performance in combined chloride–sulfate solution than sulfate solution. Ben-Yair (1974) also achieved the same result in their studies. Maes and De-Belie (2014) believe that sulfate destruction is delayed in presence of chloride ions. Lee et al. (2008) used water-containing chloride and concluded that presence of chloride ions in sulfate environment reduces sulfate attack in OPC especially in high water cement ratios. Generally, most researchers believe that chloride ions have mitigating effect on sulfate attack (Lee et al. 2008;
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