Sulfate resistance of mortars using fly ash as a partial replacement for Portland cement
Abstract
The sulfate resistance of motors that use fly ash as a partial cement replacement with control mortars that do not contain fly ash were compared. Fly ash from four different sources and at three different replacements, 10%, 15% and 20%, by weight, were evaluated. Three of the fly ashes satisfied ASTM C618, Class F, specifications and one fly ash met all requirements except for the available alkalies. A single portland cement source, meeting the ASTM specifications for Type II, was used. One by one by eleven inch mortar bars were subjected to a mixed (sodium and magnesium) sulfate solution environment. Physical measurement of mortar bars include length change, weight change, porosity and relative dynamic modulus. Improvements in sulfate resistance over that provided by a Type II cement may be obtained through the use of certain fly ashes in portland cement concrete. Three of the ashes studied significantly improved sulfate resitance as indicated by percent expansion.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- February 1982
- Bibcode:
- 1982STIN...8310305R
- Keywords:
-
- Cements;
- Fly Ash;
- Mortars (Material);
- Sulfates;
- Calcium Compounds;
- Cracking (Fracturing);
- Durability;
- Hydroxides;
- Silicates;
- Engineering (General)