Abstract
This study is the first attempt to investigate the possibility of incorporating nano-activated carbon (nAC), prepared from residual biomass of olive trees, on the properties of alkali-activated slag (AAS) pastes. After suitable preparation of nAC, it was added into AAS pastes at various levels starting from 0.5 to 3.5, by weight. The results of workability, compressive strength, total porosity and drying shrinkage were measured. Different techniques such as X-ray diffraction (XRD), thermogravimetric analysis (TGA) and its derivative (DTG), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) were used to identify the hydration products and the microstructural development of the AAS pastes with/without nAC. The results showed a negative effect of nAC on the workability of the mixtures. The incorporation of 1.5% nAC showed the highest compressive strength, the lowest total porosity and drying shrinkage. The incorporation of 3.5% nAC led to a reduction in the compressive strength and an increase in the total porosity and drying shrinkage. It can be concluded that the incorporation of suitable ratios of nAC can be beneficially used to resolve one of the main problems of AAS (i.e. drying shrinkage). Thus, the addition of nAC could enhance the probability of utilizing AAS as a good alternative to Portland cement.