Displaying items by tag: performance

US: A team from the Massachusetts Institute of Technology (MIT) has developed a new method to sequester CO₂ in concrete before curing it. The method is based on the addition of bicarbonate of soda, which reacts with cement to produce a calcium carbonate-calcium silicone hydrate composite. The Journal of Engineering has reported that the method adds the benefits of CO₂ mineralisation during production and casting, doubling the mechanical performance of early-stage concrete. It also eliminates the effects of carbonation reactions in cured concrete, which weaken the concrete by lowering its alkalinity, which accelerates the corrosion of rebar. The method has the potential to sequester 15% of CO₂ emissions from cement production.

The team said “The pre-curing capacity of concrete to sequester CO₂ has been largely underestimated and underutilised. Our new discovery could further be combined with other recent innovations in the development of lower carbon footprint concrete admixtures to provide much greener, and even carbon-negative, construction materials.”

US: Prometheus Materials’ microalgae-based biocement has secured certification for use in concrete masonry unit (CMU) mixes. The cement now holds an ASTM C129 certificate for use in non-loadbearing CMUs and an ASTM C90 certificate for use in loadbearing CMUs. Prometheus Materials’ biocement produces concrete with comparable or superior mechanical, physical and thermal properties to ordinary Portland cement (OPC)-based concrete. It offers little-to-no CO₂ emissions and 95% of water used in production is recycled.

Prometheus Materials CEO Loren Burnett said “We are thrilled to have achieved these two foundational certifications as we proceed in full force with our goal of decarbonising construction. Prometheus Materials’ product is poised to change the future of construction, converting one of the most carbon-polluting industries to a low-carbon – and one day net-zero carbon – reality.”

Namibia: Ohorongo Cement Namibia has supplied 3000m³ of cement to the site of NamPower's upcoming Sekelduin power plant in Swakopmund. Ohorongo Cement used 730t of its CEMIR cement, which contains 30% fly ash, combined with an additional 30% fly ash in the concrete mixer. The producer said that the extra ash increases the finished product's density, reducing permeability.

Ohorongo Cement said that the project is 'near completion,' having begun in mid-2021.