چكيده به لاتين
Alkaline cement binders offer innovative and ingenious solutions to combat global energy demand, waste generation, and greenhouse emissions. Hybrid alkaline cement (HAC) is regarded as a new binder which is composed of more than 70% supplementary cementitious materials (SCMs), less than 30% Portland cement and a small dosage of alkali activator.In their production, alkaline binders consume waste materials with less energy and emit less CO2 compared to ordinary Portland cement.This cementitious material possesses the advantages of Portland cement and alkali-activated materials (AAMs) and provides more compact microstructure, high strength. In this study, the possibility of using hybrid cement consisting of Portland cement, volcanic ash and grand granulated blast furnance slag with different amount of alkali activator (5,10% Na2SO4) in stabilization and improvement of clay soil during processing at 7,28 and 90 days at ambient temperature was investigated.therefore the effect of increasing the amount of binder and the amount of activator as well as the curing time on the strength of the samples has been investigated. The Unconfined Compressive Strength (UCS), freeze-thaw and wet-dry durability tests, X-ray diffraction (XRD), FESEM-EDS-Mapping and FTIR analysis have been utilized to study the mechanical,durability and microstructural properties of the stabilized soil respectively. The results of this study showed that by adding a small amount of cement to these binders, due to the fact that the amount of CaO in the composition increases, their curing and setting at room temperature is possible, also due to the slag hydration occurs in ambient temperature,slag performed better than volcanic ash.In addition,with increasing the amount of activator and curing time, the samples achieved higher strength and denser microstructure. So that the sample consisting of slag and 10% activator reached a strength of 10.45, which is 13.95% higher than the strength of the reference cement sample. The results of durability tests also showed that hybrid cement in both wet-dry, freezing-thaw has a very good performance against Portland cement. Moreover, all of the microstructural analysis supports the mechanical results.
