Construction World June 2019

PRECAST CONCRETE PRODUCTS

Poor aggregates? NO PROBLEM

Contractors seeking consistent quality concrete in situations where poor or variable quality aggregates are the norm can dramatically improve results with the addition of an innovative new product from construction chemical manufacturer, Mapei.

A ccording to Servaas le Roux, product manager concrete admixtures, the company’s new Dynamon MS 100 product is an acrylic-based admixture for concrete where the variations in aggregates won’t affect the concrete characteristics severely. “This technically advanced product is formulated to deal with aggregates in ready-mix and precast concrete containing high amounts of fine parts such as clay and mica which use more water than necessary. It lowers the water demand of such aggregates, allowing manufacturers stable manufacturing conditions even though the raw materials are not that stable. It is mainly used by concrete manufacturers to produce fluid concrete.” Super plasticising A further advantage of using Dynamon with less than the best materials is it counteracts minerals that might make super plasticizing the admixture less efficient. It means a lower dosage of super plasticisers is needed but at the same time allows longer workability retention of the mix. Although it is suitable for concrete production of any type, it is particularly well suited to produce high consistency concrete, self-

consolidating concrete, pumped concrete and fair face concrete. Mapei has a range of products complementing the Dynamon MS 100 including super plasticizers in the same Dynamon range, viscosity-modifying, fume-based powdered and retarding admixtures. The company also recommends additional products to improve specialised concrete production such as Expancrete, which is an expanding agent used in the production of shrinkage- compensated concrete. Then there are form-release compounds from the Mapeform Eco range and DMA used to strip formwork from concrete. Contractors would also find the curing agents from the Mapecure range useful to protect concrete from rapid water evaporation. Completing the range are fly-ash, lime-based fillers, blast furnace slag and pozzolan. Application Dynamon MS 100 is supplied in a ready-to-use liquid form and can be added either to the mixing water or right after all the other components such as cement, aggregates and mineral additives have been added. After adding, Mapei SA recommends extended mixing time to ensure an even distribution of it in the mix. It is most effective if applied in fluid concrete with a super plasticiser. 

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CONSTRUCTION WORLD JUNE 2019