Title: Resistance of High Strength Concrete to Sulfate Attack: Soaking and Drying Test

Author(s): Ivan Ramalho de Almeida

Publication: Symposium Paper

Volume: 126

Issue:

Appears on pages(s): 1073-1092

Keywords: absorption; compressive strength; fly ash; high-strength concretes; permeability; porosity; pozzolans; silica fume; sulfate attack; superplasticizers; Materials Research

DOI: 10.14359/2498

Date: 8/1/1991

Abstract:
The sulfate resistance of concretes with compressive strengths between 60 and 110 MPa was evaluated. The test comprises several soaking/drying cycles of samples in a Na2SO4ù10H20 solution, followed by measurement of mass variation and residual compressive strength. Visual inspection and sulfate recovery by distilled water immersion increased the accuracy of test results. Results reveal significant differences compared to those tests normally used, involving prolonged immersion. The resistance to sulfate attack depends on concrete porosity and capillary absorption and not on permeability, because pozzolanic reactions seem to interrupt pore continuity. The reduced water-cement ratio obtained with the aid of the superplasticizer was much more effective than the chemical characteristics related to the presence of mineral admixtures in concrete regarding its resistance to sulfates.