Displaying items by tag: admixtures

US: A research team at Washington State University has developed admixtures using chitin derived from seashells. The Moscow-Pullman Daily News has reported that the substance enhances concrete’s performance when substituted for some of the cement content. The lower clinker factor may also decrease net emissions. Work has shown that lower volumes of the supplementary material are required compared to existing admixtures.

Qatar: Switzerland-based Sika has expanded concrete admixture production capacity at it Doha admixture plant. The company has also announced the start of epoxy resin production in the country. It says that its present investments target growth to serve the expanding regional construction market. Numerous major projects and the expansion of energy and utilities infrastructure have driven a growing demand. Qatar’s state sourcing policy further increases consumption of building materials produced in the country.

Europe, Middle East and Africa regional manager Ivo Schädler said "Our latest investment in Qatar positions us for continued growth and strengthens our competitiveness in the country. In expanding our production, we are anticipating a substantial increase in demand and volumes for our high-value adhesives and flooring solutions. Our building sector customers will benefit from an expanded and locally produced portfolio of Sika solutions which, in addition, eliminates long-distance transportation."

UK: The Mineral Products Association (MPA) has announced the accession of a new affiliate member, the Cement Admixtures Association (CAA). The CAA represents admixture producers that supply construction and civil engineering in the UK. It was a founding signatory of Construction Industry Sustainable Construction Strategy in 2008.

MPA chief executive officer Nigel Jackson said, “We are delighted to have the CAA and its members as affiliates of the MPA. We look forward to increasingly close collaboration on our common objectives to improve the sustainability of key mineral products and promoting best practice in concrete and masonry construction.”

Cement and concrete products with sustainability credentials have increased in recent years as societies start to demand decarbonisation. In spite of the recent drop in the European Union (EU) Emissions Trading Scheme (ETS) price, there has been a trend in recent years in the construction industry towards offerings with better environmental credentials. Indeed, this week’s position paper from Cembureau on a carbon border mechanism concerns directly the growth of these kinds of products within Europe. Typically, the higher profile projects have been slag cement or concrete implementations such as Hanson’s use of its Regen cement substitute in a London sewer project or David Ball Group’s Cemfree concrete in a road project also in the UK. In this short review we’ll take a selective look at a few of the so-called low carbon cement and concrete products currently available.

Table 1: Some examples of methods to reduce embodied CO₂ in cement and concrete. Note - the product examples are selective. In some cases many other products are available.

Looking at cement first, the easiest way for many producers to bring a lower carbon product to market has been to promote cements made using secondary cementitious materials (SCM) such as granulated blast furnace slag or fly ash. These types of cements have a long history, typically in specialist applications and/or in relation to ease of supply. For example, cement producers in eastern India often manufacture slag cements owing to the number of local steel plants. However, cement producers have more recently started to publicise their environmental credentials as they reduce the clinker factor of the final product. Alongside this though, in Europe especially, a number of so-called low carbon cement producers have appeared on the scene such as EcoCem and Hoffman Green Technologies. These newer producers tend to offer SCM cement products or other low carbon ones built around a grinding model. It is likely that their businesses have benefitted from tightening EU environmental legislation. How far cement producers can pivot to SCM cement products is contentious given that slag and fly ash are finite byproducts of other industries that are also under pressure to decarbonise. Although it should be noted that other SCMs such as pozzolans exist.

As will be seen below a few of the methods to reduce embodied CO₂ in cement and concrete can be used in both materials. SCMs are no exception and hold a long history in concrete usage. As mentioned above David Ball Group sells Cemfree a concrete product that contains no cement. Harsco Environmental, a minerals management company, invested US$3m into Carbicrete, a technology start-up working on a cement-free concrete, in late 2019.

Limestone calcined clay cements are the next set of products that are starting to make an appearance through the work of the Swiss-government backed LC3 project, more commercial offerings like FutureCem from Cementir and H-EVA from Hoffman Green Technologies and today’s announcement about ThyssenKrupp’s plans to fit the Kribi cement plant in Cameroon with its Polysius activated clay system. They too, like SCM cements, reduce the clinker factor of the cement. The downside is that, as in the name, the clay element needs to be calcined requiring capital investment, although LC3 make a strong case in their literature about how fast these costs can be recouped in a variety of scenarios.

Calcium silicate cements offer reduced process emissions by decreasing the lime content of the clinker lowering the amount of CO₂ released and bringing down the temperature required in the kiln to make the clinker. Solidia offers its calcium silicate cement as part of a two-part system with a CO₂ cured concrete. In the US LafargeHolcim used Solidia’s product in a commercial project in mid-2019 at a New Jersey paver and block plant. Solidia’s second core technology is using CO₂ to cure concrete and reducing water usage. They are not alone here as Canada’s CarbonCure Technologies uses CO₂ in a similar way with their technology. In their case they focus more on CO₂ mineralisation. In Germany, Schwenk Zement backed the Celitement project, which developed a hydraulic calcium hydro silicate based product that does not use CO₂ curing. Celitement has since become part of Schwenk Zement.

Solidia isn’t the only company looking at two complementary technologies along the cement-concrete production chain. A number of companies are looking at recycling concrete and demolition waste. Generally this splits into coarse waste that is used as an aggregate substitute in concrete and fine waste that is used to make cement. LafargeHolcim has Evopact for the coarse waste and Susteno for the fine. HeidelbergCement has EcoCrete for the coarse and is researching the use of fines. Closing the loop for heavy building material producers definitely seems like the way to go at the moment and this view is reinforced by the involvement of the two largest multinational producers.

Of the rest of the other low carbon cement methods detailed in table 1 these cover other non-Ordinary Portland Cement (OPC) such as geopolymer and calcium sulphoaluminate cements. The former are a type of alkali activated binder and generally lack common standards. The latter are similar to slag cements in that they are established specialist products with lower CO₂ emissions than OPC.

With concrete when trying to make a low carbon product the first choice is whether to choose a low-carbon cement as the binder or even not to use cement at all in the case of Regen or Cemfree. From here the next step is to simply use less cement in a concrete mixture. There are a number of ways to do this from optimising aggregate gradation, following performance specifications more closely, using strength tests like maturity methods and generally adhering to quality control protocols better to deliver more consistency. Read the Mineral Production Association (MPA) publication Specifying Sustainable Concrete for more detail on this. Using concrete admixtures can also help make concrete more sustainable by improving quality and performance at construction sites through the use of plasticisers and accelerators, by decreasing embodied carbon through the use of water reducers and by improving the whole life performance of concretes. The use of locally-sourced aggregates is also worth noting here since it can reduce associated transport CO₂ emissions.

More novel methods of reducing embodied CO₂ emissions in concrete include the use of geopolymer concrete in the case of Zeobond Group’s E-Crete or adding graphene as Concrene does. Like geopolymer cements, geopolymer concretes are relatively new and lack common standards. Products like Concrene, meanwhile, remain currently at the startup level. Finally, if all else fails, offsetting the CO₂ released by a cement or concrete product is always an option. This is what Cemex has done with its Vertua Ultra Zero product. The first 70% reduction in embodied CO₂ is gained through the use of geopolymer cement. Then the remaining 30% reduction is achieved through a carbon offsetting scheme via a carbon neutral certification verified by the Carbon Trust.

As can be seen, a variety of methods exist for cement and concrete producers to reduce the embodied CO₂ of their products and call them ‘low-carbon.’ For the moment most remain in the ‘novelty section’ but as legislators promote and specifiers look for sustainable construction they continue to become more mainstream. What has been interesting to note from this short study is that some companies are looking at multiple solutions along the production and supply chain whilst others are concentrating on single ones. The companies looking at multiple methods range from the biggest building material producers like LafargeHolcim and HeidelbergCement to smaller newer ones like Solidia and Hoffman Green Technologies. Also of note is that many of these products have existed already in various forms for a long time like SCM cements and concretes or the many ways concretes can be made more sustainable through much simpler ways such as changing aggregate sourcing or working more efficiently. In many cases once markets receive sufficient stimulus it seems likely that low carbon cement and concrete products will proliferate.

Global Cement is researching a market report on low carbon cement and concrete. If readers have any comments to make please contact us at This email address is being protected from spambots. You need JavaScript enabled to view it.

Germany/Switzerland: LafargeHolcim has reportedly placed a bid for BASF Construction Chemicals, according to sources quoted by Bloomberg. The cement producer has reached the second round of the bidding processing, along with companies including Bain Capital, Cinven and Standard Industries. The auction of the subsidiary of BASF that produces admixtures, mortars and grouts is expected to reach as much as Euro3bn. LafargeHolcim chief executive officer (CEO Jan Jenisch said in May 2019 that the company is considering at least 10 bolt-on assets purchases for 2019.

Qatar: Sika is starting operation at a new concrete admixture plant in Doha. The site will include production lines for concrete-admixture manufacturing as well as a main office and a central storage facility. The new plant follows the establishment of the national subsidiary in 2012.

"The optimisation of our supply chain will enable us to play an even greater role in major construction projects in Qatar. Having our own production capacities available locally makes it possible for us to lower transportation costs and enhance proximity to customers," said Ivo Schädler, EMEA Regional Manager for Sika.

France: Fives Group has tested using its FCB Rhodax cone crusher to process concrete wastes resulting from the demolition and deconstruction industry. During an internal innovation competition, the crusher was used to sort hydrated cement paste from the aggregates and sand. The development will enable cement producers to reuse the paste as a cement additive. Ready mixed concrete producers will be able to make new concrete using the recycled aggregates and sand allowing for a reduction in CO₂ emissions. Fives hopes to turn demolition concrete waste into a valuable commodity.

China: Germany’s Wacker Group has opened a new competence centre for cement and concrete applications in Shanghai. The laboratory will develop silicone based products and solutions which are able to improve the performance of cement and concrete and to make these materials more sustainable. Special focus is on silicone admixtures and performance enhancers.

“As a regional innovation platform focusing on cement and concrete, the new lab will cooperate with leading Chinese universities, research institutions and the industry. Its goal is to develop innovative products and solutions which support the sustainable development of the Chinese construction materials industry,” said Paul Lindblad, president of Wacker Greater China.

At its new competence centre in Shanghai, Wacker will be able to investigate how silicone chemistry can protect cement and concrete against environmental influences and, at the same time, improve the durability of these materials.

China: Anhui Conch has chosen Conch New Materials, a fellow subsidiary of Conch Holdings, as one of its grinding aids suppliers for 2019 following an open tender process. The value of the deal is estimated to be worth no more than around US$125m for no more than 0.15Mt of cement grinding aids. Conch New Materials develops, produces and sells cement additives, concrete admixtures, related chemical products and technical services. The other supplier has not been named.

US: GCP Applied Technologies’ net sales from its Specialty Construction Chemicals division grew by 5.9% year-on-year to US$165m in the third quarter of 2018 from US$156m in the same period in 2017 due to higher volumes in its Concrete and Cement businesses. Overall, the company’s net sales rose by a similar percentage. It manufactures a range of additives for cement production under the Opteva and Tavero brands.