Developing thermal insulation cement-based mortars using recycled carbon black derived from scrapped off-the-road tires

This study appraised the feasibility of recycled carbon black (RCB) derived from scrapped off-the-road (OTR) tires, denoted as RCB-OTR, as aggregates to develop thermal insulation mortars. Sand in Ordinary Portland cement (OPC)-based mortars was replaced by RCB-OTR in volumetric proportions of 0, 30, 60, and 100%. The results revealed that the developed thermal insulation mortars had oven-dry densities between 1058 & PLUSMN; 1 and 2045 & PLUSMN; 5 kg/m3 and 28-day UCS between 8.6 & PLUSMN; 0.74 and 37.3 & PLUSMN; 0.76 MPa. Mortars at RCB-OTR replacement ratios below 30% can be employed as load-bearing units. Replacing all sand with RCB-OTR resulted in a considerable decrease in thermal conductivity from 1.800 & PLUSMN; 0.071 to 0.272 & PLUSMN; 0.021 W/mK, the volumetric heat capacity from 1.438 & PLUSMN; 0.063 to 1.044 & PLUSMN; 0.079 MJ/m3K, and thermal diffusivity from 1.255 & PLUSMN; 0.089 to 0.263 & PLUSMN; 0.034 mm2/s. Overall, mortars mixed with RCB-OTR exhibited good thermal insulation performance and satisfactory mechanical properties, demonstrating that RCB-OTR is a promising lightweight aggregate for thermal insulation building materials. This is the first study to incorporate RCB-OTR into the cement-based materials and evaluate the thermal properties. It contributes to the development of eco-friendly thermal insulation building materials using RCB-OTR and delivers an innovative solution for mining industry to dispose of waste OTR tires.

Automated summary

This study explores the feasibility of using recycled carbon black (RCB) derived from scrapped off-the-road (OTR) tires, denoted as RCB-OTR, as aggregates in thermal insulation mortars. The results show that mortars with RCB-OTR exhibit good thermal insulation performance and satisfactory mechanical properties. The study contributes to the development of eco-friendly thermal insulation building materials and offers a solution for disposing of waste OTR tires in the mining industry.