Investigation of one-part hybrid alkaline cement with heat-treated aluminosilicate activator

This paper presents an experimental analysis of the effect of dry alkali activator dosages on strength of hybrid alkaline cement paste. The precursor was composed of 80% fly ash and 20% of ordinary Portland cement (OPC). The dry activator was prepared by heating the mixture of trass and sodium hydroxide and termed as TRN. The activator and the precursor were dry-mixed by hand in a mortar and pestle and then added with a certain amount of water, as conducted on ordinary cement. The compressive strength tests were performed on 20mm x 40mm cylinder paste specimens after 7 and 28 days of casting. The control specimen without activator was acquired by the same procedure of the observed samples. Scanning Electron Microscopy (SEM) was applied to evaluate fly ash morphology as well as paste fracture surface and matrix compactness. X-ray diffraction (XRD) was conducted for evaluating the pattern difference between 0.27W sample (without activator) and TRN1.5 sample. It is found that the paste strength increasing significantly as consequence of the introduction of 1.5% of TRN activator. This result agreed with decreasing of quartz peak of XRD pattern in TRN1.5 sample compared to 0.27W sample and denser TRN1.5 matrix than 0.27W observed by SEM.