Boral, Holcim lead the race to solve ‘green’ concrete’s challenges

Concrete production contributes 7% of global CO2 emissions, which is not far behind steel. But unlike steel, efforts to decarbonise concrete have been plagued by challenges, both technical and perceptional.

Like steel and aluminium, concrete is a foundational pillar ofthe net zero economy. It is everywhere, from roads, tofactories and buildings and is not going away any time soon. 

The challenge is to reduce the emissions profile of clinker, one of thekey ingredients in cement, the main ingredient in concrete. Currently,concrete manufacturing generates up to 7% of global carbon dioxideemissions, making it a major contributor to climate change. 

But unlike steel and aluminium, most of the solutions fordecarbonising concrete are known, proven and have been in use insome way shape or form for decades. Experts say the reason why we haven’t fully decarbonised the cement making process mainly comes down to perception and logistical issues, rather than technical constraints. 

Concrete is emissions-intensive due to the release of CO2 when limestone is converted into clinker, the building block of cement. Thisaccounts for around 65% of total emissions, with the remaindercoming from fossil fuels used to heat cement kilns, electricity used tomix concrete and transportation. 

To date, decarbonisation efforts have been mainly focused on two areas; either reducing the quantity of cement in a concrete mix or replacing some of the concrete with “supplementary cementitious materials” (SMCs) that contain less embodied carbon; or using renewable fuels to heat kilns and power cement mixers. 

Ready-mix concrete companies like Boral and Holcim already have what they term “low-carbon” concrete products on the market, which use either fly ash which is a waste product from coal-fired power plants, or slag taken from blast furnaces in place of Portland cement to lower the carbon content. 

Read the full article, published by Capital Brief, here.