Title:
Durability of Portland Cement-Silica Fume Pastes in Magnesium and Sodium Sulfate Solutions
Author(s):
Menashi D. Cohen and Arnon Bentur
Publication:
Materials Journal
Volume:
85
Issue:
3
Appears on pages(s):
148-157
Keywords:
cement pastes; deterioration; durability; ettringite; expansion; failure mechanisms; gypsum; magnesium hydroxides; magnesium sulfates; portland cements; silica fume; sodium sulfates; strength; sulfate attack; Materials Research
DOI:
10.14359/1809
Date:
5/1/1988
Abstract:
The effects of magnesium sulfate (MS) and sodium sulfate (NS) solutions on the durability of 0.3 water-to-solid ratio pastes of ASTM Types I and V portland cements with partial replacement of 15 mass percent silica fume were investigated. Results show that silica fume addition to portland cement can improve resistance to sodium sulfate attack, but it can greatly impair resistance to magnesium sulfate attack. The need for establishing failure criteria/performance classifications for sulfate resistance is amplified. These criteria/classifications depend primarily on the mixture proportions, curing, duration, and type of sulfate exposure, and indicator (i.e., change in length, mass, compressive/flexural strength, and modulus of elasticity). These classifications should allow one to point out the specific nature of the sulfate attack (i.e., expansion/cracking and/or softening/spalling) and to distinguish differences in resistance between pozzolanic C-S-H and the portland cement C-S-H gels.