From sugar cane to concrete

Sustainability and resource efficiency are key topics in the concrete industry, also since cement industry is responsible for about 5% of the global carbon emissions and concrete production uses large amounts of water and aggregates.

It is a known fact that Sika’s ViscoCrete superplasticizer technology, based on Polycarboxylate ether (PCE), allows reducing water and cement in high volume concrete, while maintaining or improving its properties. As most chemical products, these are oil based materials. A new step has been made at Sika India’s concrete admixture site, where the Sika ViscoCrete raw materials are now being produced based on by-products from renewable raw materials instead of oil, without compromising the quality.

For the synthesis of biobased PCE superplasticizer, polyethylene glycol is synthesized by a unique process, using molasses, which is a by-product from sugar production, as feedstock. When using plant-based materials to produce biofuels or other chemicals, there is always the question whether such crops and land should otherwise be used for agriculture and human consumption. However, since this raw material is obtained from a by-product of sugar production, these raw materials are not competing with products which could be used for food production.

Bio carbon in, carbon footprint out
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Bio carbon in, carbon footprint out

The synthetic route for both types of polymers is shown on the left (enlarged photo).

The calculated biobased carbon content of these superplasticizers is more than 80%. In addition, these raw materials have a lower carbon footprint than the conventional, oil based ones. Taking into account the amount of polyethylene glycol used in Sika India production site, this currently amounts to approximately saving 140 tons CO2-eq per year.