Constructing with chemistry

The cement, concrete, and aggregates sectors are committed to the abatement of CO₂ emissions, execution of sustainable construction, and circularity. A 2050 Cement and Concrete Industry Roadmap for Net Zero Concrete has been established by the Global Cement & Concrete Association (GCCA), a CEO-led not-for-profit international association, delineating the levers and activities that need to be executed to decarbonise the industry.

Behind the GCCA commitments are the daily efforts of the companies who are contributing through investments and execution of projects in each of the levers, and amongst the efforts, chemical admixtures play a key role as an enabler of various initiatives.

According to McKinsey & Company, admixtures have a potential to contribute to the reduction of CO₂ in the construction materials industry up to 50%.This article highlights how chemical admixtures will increasingly gain importance as the need and challenges to introduce new technologies in cement, concrete, and aggregates will become vital to reach net zero.

The first ‘industrialised’ use of chemicals such as milk, animal fat, egg whites, molasses, or blood in construction materials dates to the Romans (300 BC to 476 AD). The Roman Architect Vitruvius, through the 10 books of ‘De Architectura’, addressed city planning, architecture, temple construction, and building materials. Vitruvius provided details on the proportioning of the constituents for Roman concrete which also included specifications of chemical admixtures that were to be used to either impermeabilise, render more workable, or enhance durability. Thus, it was recognised already then, that the addition of chemicals to concrete was essential to enhance the performance of the material. Centuries later, with the advent of modern cement in 1824 by Joseph Aspdin, the formal adoption of chemical admixtures resurfaced in 1933, and since then admixtures have played a fundamental role in improving and, more importantly, enabling clinker grinding efficiency, increasing clinker reactivity, reducing the water demand of concrete and increasing its fluidity, allowing for clinker to be substituted by supplementary cementitious materials (SCMs) and mineral additions, accelerating construction times, and impermeabilising cement-based materials. Current state-of-the-art chemical admixture technology is a testament to the important strides made to enable and therefore technologically advance the performance of concrete.

The emerging new ‘Green Economy’ is stimulating worldwide efforts to stop climate change and is a driver inducing the construction industry to evolve and resolve challenges related to GHG emissions, circularity, and sustainability in construction practices. Consequently, as indicated in the GCCA Roadmap to Net Zero, the construction materials industry will need to rely on innovations if it is to reach the net zero target by 2050.

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Read the article online at: https://www.worldcement.com/special-reports/23092024/constructing-with-chemistry/