Tool box of admixtures to produce better, greener concrete
Greater demands are being placed on concrete – a building block of our civilization – to reduce building costs and its footprint on the environment. This is the reason why construction chemical companies such as CHRYSO are constantly formulating and manufacturing new and improved admixtures that assist in producing concrete that is more suited to the ever more challenging requirements made by engineers and contractors.
Speaking at SARMA’s recent readymix conference, Marc Plancon, marketing director for the CHRYSO Group explained that due to urbanization, readymix plants are situated further from construction sites. There is also a move towards vertical construction in big cities where space is at a premium as well as an increase in underground construction.
“Traditional concrete simply cannot keep pace with modern requirements and for this reason advances in admixtures are becoming increasingly important to produce modern concrete. There are many drivers behind the requirement for these products, but first and foremost it is about sustainable development, faster construction, as well as improving the characteristics of concrete. “This is being hastened by new integrated design structures; and build-own-operate (boo) – where a builder owns the building and needs the quickest possible return on construction investment. In order to operate profitably these new-age builders also need durability with less maintenance. “In developed parts of the world there is a move towards sustainable development with the use of recycled materials becoming commonplace, as well as using more geopolymers and more manufactured aggregate. This has led us to develop new admixture technology to assist with meeting these and many more requirements,” said Plancon.
He added that the admixtures available nowadays are vast and that the average concrete producer can compile a “toolbox” of admixtures that can enable them to produce almost any kind of concrete required. The admixtures include anything from water reducers, workability enhancers, place-ability, finish-ability and durability enhancers. These allow producers to save money and make money. “Usually the cost of an admixture is minimal compared to the required outcome.”
The company also continues to develop and produce new admixtures to add to the toolbox. The admixtures are essentially concrete performance boosters that can alter concrete properties such as its slump, rheology, early strength, durability and shrinkage. One of the most significant developments, however, is in the robustness of the formulas being developed that means that mix designs don’t have to be changed but the new admixtures are robust enough to withstand a wide range of mix parameters and accommodates different dosing and mix ratios without impacting performance of admixtures. Rheology robustness enhancers for example even allow for course sand to be used in place of aggregates, eliminates bleeding, improves concrete cohesion and does not have an impact on performance. New polymers also allow free flow concrete to be produced without losing its cohesive properties. This helps for pumping concrete long distances onto high rise buildings
“The good news is that we have solutions for most known challenges and if there is something specific that is required, we may be able to achieve the results by combining different types of admixtures or even developing new admixtures as required. But, either way, it requires the right technical support to make sure that it will meet the requirements of placement, curing, overall characteristics, durability and strength,” Plancon concluded.
Sarma, Johan van Wyk, Tel: (011) 791 3327, Fax: 086 647 8034, Email: [email protected], Web: www.sarma.co.za