Analysing the potential use of a low-grade magnesium carbonate by-product as a filler in hot asphalt mixtures

Climate change and the depletion of natural resources are causing society to adopt more environmentally sustainable approaches. In areas such as construction and civil engineering, waste and by-product valorisation could help in the fight against climate change, reducing the consumption of raw materials. Thus, the use of residues or by-products in asphalt mixture manufacturing as road pavement layers has great potential due to their characteristics. This study aimed to characterise a flotation sterile (low-grade magnesium carbonate; LG-MC) generated in the beneficiation process of natural magnesite and to analyse its potential as a filler in asphalt mixture manufacturing. The physical, chemical, and microscopic properties of LG-MC were characterised and its potential use as a filler for asphalt mixtures was evaluated using the UCL (Universal de Caracterizacion de Ligantes) method. The optimum filler/bitumen ratio for LG-MC was 1.49, higher than the 1.33 of calcium carbonate. Results showed a protective effect of LG-MC against ageing both in the short and long- term, reducing losses from abrasion.

Automated summary

Climate change and the depletion of natural resources are driving society towards more environmentally sustainable practices. In the fields of construction and civil engineering, the utilization of waste and by-products can help reduce raw material consumption. This study investigates the potential of using flotation sterile as a filler in asphalt mixture manufacturing, finding that it offers protective effects against aging and abrasion.