EFFECTS OF GRINDING ADDITIVES (INDUSTRIAL BY-PRODUCTS) ON THE HARDENING PERFORMANCE OF PORTLAND CEMENT

摘要

The paper presents the hardening performance of two types of cement obtained by grinding ordinary Portland and Ferro Portland cement clinkers with industrial byproduct surfactants. To this end, three categories of surfactants, such as (ⅰ) surfactants prevailing in the phthalic group or similar mixed groups, (ⅱ) blends of surfactants containing phthalic, phenolic and/or glycolic groups, and (ⅲ) blends of surfactants containing polyglycols, were employed. The additive ratios ranged from 0.03% to 0.50%, depending on case. Determinations of water demand for a normal consistency paste, soundness, setting time, and bending and compressive strengths were carried out on cement samples approx. of 4000 cm~2/g Blaine. The results have been discussed as compared to reference samples (i.e. without grinding surfactants) and in relation to the grinding surfactant category. There were pointed out the conditions in which the presence of surfactants not only is no hinder in the hardening performance of the cement, but also leads to a similar or better hardening performance than the reference cement. Particularly, the situations in which the employed surfactant bears notably favourable effects on the intergrinding were revealed.