Long-Term Efficiency of Silica Fume in Terms of Sulfate Resistance of Concrete Immersed in Sulfate Solutions and Seawater


Erdoğdu Ş. , Kurbetci Ş. , Nayır S.

IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF CIVIL ENGINEERING, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2021
  • Doi Number: 10.1007/s40996-021-00750-4
  • Title of Journal : IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF CIVIL ENGINEERING
  • Keywords: Concrete, Strength loss, Durability, Sulfates, Seawater, Silica fume, SODIUM-SULFATE, MAGNESIUM-SULFATE, ATTACK, MORTARS, PERFORMANCE, PLAIN, DETERIORATION, CEMENTS, DEGRADATION, DURABILITY

Abstract

This study aims to assess the long-term efficiency of silica fume used in the production of concrete exposed to sulfate solutions and seawater. The sulfate solutions used in the study were sodium sulfate and magnesium sulfate, and the seawater was provided from Black sea. The experimentation has continued for 4 years. The sulfate ion concentration of the sodium and magnesium sulfate solutions was adjusted to be 1300 ppm, which would be equivalent to the sulfate ion concentration of the seawater used in the test program. The total binder was 350 kg/m(3), and cement was replaced by silica fume at a ratio of 10%. The concrete prisms produced were 40 x 40 x 160 mm standard prisms. In order to evaluate the efficiency of silica fume preventing sulfate attack, mass variation along with strength change has been taken into consideration as well as observational evaluation implemented throughout the experimentation. Concrete prisms cured under standard curing conditions were also produced for comparison purposes. Considering the compressive strength, seawater seemed particularly detrimental for concrete that does not contain silica fume. Hence, regarding the compressive strength change of concrete, it is realized that it is worth to take particularly into account the seawater effect in addition to the effect of sulfate solutions. The strength deterioration process of concrete prisms immersed in sodium and magnesium sulfate solutions seemed to be associated with the loss of stiffness and cohesiveness rather than expansion and cracking as opposed to the deterioration observed in case of seawater immersion. Visible cracks were formed in the prisms that did not contain silica fume immersed in seawater.