Influence of Corrective and Additive Raw Materials on Clinker Composition and Cement Properties: A Case Study from Yemen

The study comprised the preparation of several cement raw mixes using both the currently used and the proposed alternative cement raw materials in Yemen. These alternatives were assessed to be substituted materials for the currently used sand-clay that mostly excavated from the valuable cultivated lands. Also, this study evaluated the effects of some proposed additive raw materials on the cement products of Yemen’s factories by determining the performance properties of their admixtures. Since the clinker phase texture gives useful information about the raw materials used and the manufacture process, the clinker phase types and their microstructures were determined using Bogue equations, XRD, SEM and EDAX techniques. The alite and belite crystals, which comprise the major phases of the produced Portland cement clinker samples, have an intimate genetic relationship with microcrystalline intergrowth of aluminate and ferrite matrix. The burning at 1350 °C was particularly suitable for most of the prepared raw mix and produced clinker samples as it led to the lowering of fuel consumption, kiln thermal load and radiation temperature as well as the preventing the breakdown of the alite to belite and free lime (F·CaO). Evidently, after the addition of the optimum percent of gypsum (5%), some of the proposed additives improve the hydration behavior and the respective performance properties of the examined clinker cement admixtures. The cement strength development is affected by the nature of the constituting clinker phases rather than the module values, pozzolanic reactions, Blaine values, reactive SiO 2 ratio and water demand of the cement admixtures.