CHARACTERIZATION AND EVALUATION OF NATURAL ZEOLITE AS A POZZOLANIC MATERIAL

This paper presents details about mineralogical and chemical composition of natural zeolite (NZ) from Harrat Shama for using it as a pozzolanic material. The structural properties and mineralogical composition of NZ were determined using XRF, XRD, FTIR, DSC, SEM-EDX as well as study surface texture and cation exchange capacity. The geopolymer paste was prepared using sodium silicate solution as activator for zeolite and incubated at 25 and 45 ºC up to 90 days. The compressive strength of NZ-based geopolymer was investigated up to 90 days. Five blended cement were designed by substitution for Portland cement by 0 %, 5 %, 10 %, 15 % and 20% of NZ. The compressive strength of NZ-OPC pastes were studied up to 90 days. The microstructure of NZ-Based geopolymer and hydrated NZ-cement pastes were tested. The results were shown that the sum of SiO2, Al2O3, and Fe2O3 content in the natural zeolite was approximately 82.71.3% and mainly composed of clinoptilolite mineral. Geopolymerization of NZ gave a good dense geopolymer matrix with high early stage mechanical properties. The NZ has shown improving early stage compressive strength of all blended cement pastes up to 7 days. The incorporation of nature raw zeolite in cement, up to 10% wt, improved the compressive strength to 7-29%. Generally, Saudi Arabian natural zeoilite (NZ) have high pozzolanic properties and could be used in the preparation of geopolymers matrix and blended cement pastes.