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The aim of this study was to examine usability of diatomite, a natural amorphous and porous raw material, as an additional blend in an effort to improve the performances of natural pozzolan-blended cements. To this aim, varying proportions of pozzolan, diatomite and pozzolan-diatomite-blended cements were prepared and chemical, physical, mechanical, mineralogical and microstructural tests were applied to the resulting cements. The test results indicated that diatomite blend may be effective in improving pozzolanic properties, reducing setting time, reducing alkali content and increasing early-ultimate strengths of pozzolan-blended cements.

The aim of the present study was to investigate the use of diatomite, which has limited use in the cement industry due to its porous structure in spite of its high reactive silica content, by modifying its porous structure with fly ash and limestone blend. To this end, physical, chemical, mineralogical and zeta potential (electrokinetic) analyses were performed on raw materials. Hydration progress was followed by using standard cement tests and X-ray, and 28-day microstructures of pastes were determined by scanning electron microscopy. Raw material test results have revealed that the particle structure of the raw materials affects the grindability of composite cements, while the Si-O− content in the zeta potentials makes it negative, and the Ca2+ content makes it positive. Standard cement test results indicate that water demand and setting time of pastes were related to diatomite ratio, and fly ash and filler limestone affected the development of strength by their electrokinetic properties.