Title:
Sulfate Resistance and Chloride Penetration Characteristics of High-Strength Concrete
Author(s):
W. A. Al-Khaja, W. A. Rasheeduzzafar, M. H. Al-Sayed, and A. A. Al-Khoder
Publication:
Symposium Paper
Volume:
149
Issue:
Appears on pages(s):
123-134
Keywords:
chlorides; compressive strength; high-strength concretes; mix proportioning; silica fume; sulfate resistance; Materials Research
DOI:
10.14359/4074
Date:
10/1/1994
Abstract:
One of the techniques proposed to improve the durability performance of concrete in aggressive environments is to use quality concrete. Much research has shown that cement composition also has a significant effect on concrete durability in sulfate-bearing soils/groundwaters and in chloride-corrosive situations. High C 3A cements have been found to be superior in terms of protection against corrosion of reinforcement, although they have a lower sulfate-resistance performance. In many situations, such as marine and Sabkha environments, chlorides and sulfates occur concomitantly and operate against concrete durability simultaneously. This study has been carried out to evaluate the sulfate resistance and chloride penetration performance of high-strength concrete. Two high-strength concrete mixes in the range of 60 to 75 MPa were designed first by using a superplasticized concrete of 0.36 water-cement ratio (w/c) and second by replacing 10 percent cement by silica fume. The control for comparison is a 25 Mpa concrete made with a 0.58 w/c. Type I portland cement has been used to provide higher chloride-binding capacity and, hence, better corrosion protection. A mixed sodium and magnesium sulfate environment has been used to evaluate sulfate resistance. High-strength concrete made with silica fume blending showed the best sulfate resistance in a sodium sulfate environment and the worst performance in a magnesium sulfate environment. Also, the normal 0.58 w/c ratio of 300 kg/m 3 cement content mix showed 1.5 times better performance than the 0.36 w/c ratio 450 kg/m 3 cement factor mix in magnesium sulfate environment. High-strength concrete showed three to four times better performance against chloride penetration compared to normal strength concrete. Use of 10 percent silica fume further improved resistance against chloride penetration.