Construction World recently spoke to Sibusiso Hlatshwayo, Managing Director of Chryso Southern Africa about how the demand for admixtures has evolved for the different disciplines in the built environment and what the trends are that drive this demand. According to Hlatshwayo, the quest for the built industry to be sustainable is one of the biggest drivers for Chryso which now, after its recent rebranding, has an even stronger sustainability focus than before.
Hlatshwayo says Chryso has seen an increase in the demand for admixtures that differ from market to market while this demand is also at different rates as it is in keeping with the conditions in the market and the demands that clients have for construction.
He says there are three factors influencing the increased need for admixtures: cost, an increased focus on sustainability and changing building needs.
“The industry has been battling and customers have increasingly needed mechanisms that can help them save costs to remain viable. The use of admixtures in concrete mixes enables the user to manipulate the properties of the mix and this leads to the use of less cement and water,” he says.
The increased need to be viable is now superseded by the need for the built environment to be sustainable. “This shift is coming from our customers who have a requirement for supplementary cementitious materials such as fly ash, slag and LC3 (limestone calcined clay cement) to create green concrete. Chryso’s technology can assist customers in this quest,” says Hlatshwayo.
The change in building methods is a third trend that drives the need for admixtures. “Increasingly, projects use precast elements such as tilt-up solutions. Casting is not done in situ but at factories and this puts pressure on these facilities and admixtures are required to speed up the process,” he says.
The Chryso chain of process
Hlatshwayo explains that Chryso adapts its admixture solutions to meet the specific needs of different construction and climatic environments. “This speaks to our core business and is why we exist. Structures on the coast, for example, are different from structures being built inland as they are exposed to more chloride attacks from salt and other elements. Our chain of process is to find a solution for a customer. It involves listening to the customers’ needs and understanding the challenges and problems. We collect samples from sites and test these at our R&D laboratory. These are characterised before we test them in application through our applications laboratory,” says Hlatshwayo.
Different options and chemistries are tested for use on the raw materials. “We pre-select three options for pre-trials that will be tested at the location where they will be used,” he says.
“We adapt our offering to the market via this value adding chain that we have built which may also include having one key account for customers who have various sites that require multiple products,” says Hlatshwayo.
South Africa’s challenges
Hlatshwayo says the diminishing skills base is the biggest challenge faced by construction and civil engineering when using concrete. “There is an increasing shortage of concrete technologists – people that have the skills and experience to understand how to work with concrete. Linked to this is the shortage of young people that enter the industry who can be taught how concrete should be managed,” he says. This means that, even if the best solutions for concrete are created, a lack of knowledge in its application will cause challenges to arise.
Chryso addresses the skills problem with the support of continuous study for employees. “It is part of our strategic imperative to invest in education in terms of concrete technology. We also participate in public programmes such as the YES (Youth Employment Service) initiative where we take in 20 students annually at the Chryso Academy. We have young people in R&D and in our application laboratories who are learning our craft of building materials engineering.”
Hlatshwayo says access to raw supplementary cementitious materials has, in various cases, become difficult. Because of the problems at our power utility, there is an erratic supply of fly ash which has led to an imbalance in the supply and demand for the correct quality of fly ash. “Our customers have been forced to use difficult fly ash in terms of quality and consistency and this may have implications down the line. Power stations are not located at the same coal deposits which means that the qualities of fly ash are not the same. There are also issues around the availability of slag which also has implications down the line,” says Hlatshwayo.
“Without being prompted, we have launched studies of the various fly ash available in the country to enable us to proactively identify problems. We have done a full characterisation and identified the deficiencies of the available fly ash and which of our technologies can be used to overcome these. This database can assist customers who are forced to use unusual fly ash,” Hlatshwayo explains.
Because aggregate is increasingly mined further away from sites, customers are forced to use difficult aggregates which also poses a challenge.
“When it comes to access to aggregates, we have a solution aimed at this. The Chryso® Quad range is a unique solution for extending the use of complex aggregates while maintaining superior concrete quality. This range has enhanced technology for difficult aggregates (excess fines or the lack of fines). It was specifically designed for aggregates that have deficiencies or pathologies, while this technology can also be used in recycling and can assist with circularity, which is a sustainability objective for Chryso,” says Hlatshwayo.
Admixtures for greener construction
Admixtures increasingly contribute to greener construction as they reduce carbon footprints, enhance durability and enable the use of alternative materials. “Sustainability in the built environment is the biggest driver for Chryso. Cement is one of the biggest emitters of CO2 gases and globally there is a drive to reduce the amount of cement that is used. Our admixtures enhance the ability of the customer to reduce water and therefore reduce the use of cement. At the same time, the aim of admixtures is to enhance the properties of the concrete – whether it be flowability, ease of placement, strength development or aesthetics.”
The transition to a low-carbon concrete mix-design is one of the main levers to meet the challenges of sustainable construction. “Towards the end of 2024, Chryso introduced EnviroMix®, a global offer of admixtures and services to optimise the concrete formulation and implementation strategy, while maintaining and enhancing performance,” he says. Both the Chryso® Quad and EnviroMix® ranges are supported with digital tools to help the customer take advantage of the benefits that it offers.
Hlatshwayo says that admixtures themselves also have to transform. “There is some carbon impact with admixtures as it is not natural. We will soon have products that utilise biomaterials to create these solutions. We call them bio-admixtures and these will be green admixtures to help the customer make concrete green. We are not just assisting our customers in their sustainability quest, but also transforming our solutions,” he adds. Chryso has a responsibility as an admixture supplier and is therefore making use of solar energy, sophisticated systems for water harvesting, and its Zero Discharge project whereby no effluent is sent into the environment with an aim of attaining a closed circuit. “We want to walk the talk when it comes to our green admixtures,” Hlatshwayo says.
Looking ahead
Hlatshwayo says that admixtures are going to be the mainstay in the future as the focus on sustainability intensifies. “We are ahead of the curve and have already launched projects, have proof of concepts and are already testing some of these new technologies,” he says.
In keeping with the increased focus on sustainability, new cements will be developed. “In 1985, South Africa only had three cement types. With the global push towards sustainability, new cement types are being added, one of these is LC3 cement. These will require a different approach in terms of activation while new binary technologies are necessary as cement will make use of more supplementary cementitious materials. We are gearing ourselves to be able to support these developments and want to be at the forefront,” he states.
The rapid rate of urbanisation will increasingly necessitate a change in building methods, the support of off-site manufacturing and 3D printing. “For each one of these new developments we are positioning ourselves to be able to provide solutions, whether it be 3D printing, urbanisation or off-site manufacturing,” he concludes.
