Assessment of the Pozzolanic Activity of Some Available Local Mineral Concrete Admixtures

This current paper aims to evaluate the pozzolanic activity of some available local mineral admixtures in order to use them in improving the engineering properties of structural concrete that's because, there is no standard specification on Egyptian Standard Specification (ESS) to be used for evaluation of the pozzolanic activity and suitability of the local mineral admixtures as a pozzolanic supplementary cementing materials. For this purpose, seven physico-chemical-mechanical methods have been used to enable of evaluating of pozzolanic activity and makes a comparison between different tested admixtures. Where, Particle size and fineness were evaluated via visual assessment and by nitrogen adsorption method. The chemical analysis of these local admixtures was determined by XRF test. As well as, in order to check the disappearance of the characteristic peaks of these admixtures, XRD testes were carried out. SEM was used to investigate the microstructure. To quantify the potential contribution of mineral admixtures on the mechanical behavior, SAI and HPF were conducted on mortar mixes containing these admixtures. The local tested admixtures are three types of (MK24, MK33 and NMK), CBC, GBB and BFS. On the other hand, commercially FA was also used and tested as a reference admixture for comparison. The results of this study concluded that, the studied assessment methods might be effectively on assistance for evaluation of pozzolanic activity of concrete admixtures which, can be used to improve concrete performance