| Abstract [eng] |
The use of alkali-activated materials can reduce CO2 emissions by reducing global warming potential by 40-70% compared to conventional Portland cement (OPC). Thus, alkali-activated binders are a viable alternative to conventional Portland cement mixtures. SEM, XRD studies and mechanical properties of the samples were used for the research. The influence of carbon nanotube blown graphene and carbon powder additives on alkali activated slag samples was investigated. Significantly higher compressive strengths were found when nanotubes were ultrasonically dispersed in water compared to dispersion in sodium hydroxide. Upon ultrasonic dispersion in an alkaline solution, the nanotubes jumped into clumps and did not distribute evenly over the cement paste, resulting in lower compressive strength. With carbon nanotubes, good results were obtained with the highest used amount of carbon nanotubes 0.25%, and when they were dispersed in water, the compressive strength was 36.8 MPa. The results of the blown graphene samples were poor, resulting in a 41.8% lower compressive strength compared to the control. The best results were obtained using a carbon powder additive, which is made from wood waste and is significantly cheaper than other additives used in this work. The compressive strength of the samples with the addition of carbon powder varies between 35.1 MPa and 39.5 MPa. Compared to the control mixture, the compressive strength is 10% higher. Carbon powder costs nothing because it is a waste from the heat treatment of biomass. For this reason, the use of carbon powder from the biomass pyrolysis process can be beneficial for new environmentally friendly building materials. |
