Agroindustrial Waste Can be Used for Housing and Infrastructure

This article by José Tadeu Arantes was published Aug. 18, 2017, on phys.org

Guidelines for a research project about agroindustrial wastes and their potential use as appropriate materials for housing and infrastructure include converting waste into resources, substituting toxic raw materials for healthy inputs, and migrating from harmful to sustainable production processes.

The Agrowaste project is coordinated by Holmer Savastano Jr. at the University of São Paulo's (Brazil) Animal Science & Food Engineering School (FZEA-USP) in Pirassununga, Brazil.

"We developed two lines of research: one with inorganic matrix composites, exploring the addition of biomass fly ash and biomass fibers to the Portland cement matrix for the production of flat or corrugated fiber cement board; the other with organic matrix composites, exploring the use of plant resin-bound biomass fibers and particles for the production of board for packaging, pallets and furniture," said Savastano.

The inorganic product line will offer an alternative to asbestos cement, while the organic line will offer an alternative to phenolic resin-impregnated particleboard and chipboard. Asbestos and phenolic resins are widely held to be carcinogenic. Notably, asbestos cement is banned in a growing number of countries (currently 69) in compliance with the recommendations of the World Health Organization (WHO).

Phenolic resins are banned in several countries, but not in Brazil. However, their days are numbered. They are not only toxic, but also unsustainable because they are refined petroleum products. "Asbestos cement was used for decades, and during that time, industry adapted to it perfectly. It seemed an unbeatable technical solution, especially thanks to its low cost, but the impact on health means other less toxic reinforcing fibers must be found," Savastano said.

"Our project has already produced results with potential technology transfer to commercial firms. Fiber cement can be used in the manufacturing of corrugated roofing as well as board, siding, and other components for the construction industry. We didn't just substitute the fiber; several adjustments had to be made to the production process, and we worked on this with firms that make fiber cement in Brazil. Specific cement curing methods were required, for example," he said.

A study led by Savastano to develop fiber cement curing technology produced fiber cement board using a mixture of cement, plastic fibers, and plant pulps. "Our approach increasingly consists of using biomass fly ash as a substitute for conventional Portland cement and plant fibers instead of plastic fibers," Savastano said.