Construction World November 2017

CLOCKWISE FROM TOP LEFT: Chryso's growing range of admixtures is changing the face of construction by broadening options for designers and contractors. Chryso admixtures offer unique technology facilitating mixing efficiency to achieve cement dispersion much quicker. Chryso's Centre of Excellence is a laboratory facility where cements and aggregates can be evaluated. Chryso admixtures are used in concrete pumping applications. Korkability is easily achieved using Chryso admixtures. Chryso recently acquired Moderne Methode – a global leader in stamped, polished and micro-topping concrete. Here, Chryso has played an important role in working with local contractors to facilitate the use of these extended cements without affecting the slump retention, workability and durability of the concrete. The use of correct admixtures facilitates further extension of the concrete and Chryso has been involved in projects where more than 50% PFA has been used. Although extended cements do reach the required strengths, they react slower; the more pure cement that is replaced, the lower is the early strength of the mix. Activators are therefore introduced to trigger the early strength characteristics of the concrete. Design mixes which include extenders must also take factors such as slump retention, setting times and strength gains into account. Typically, slump retention ensures extended workability and is considered a critical characteristic of concrete on projects today, especially given some of the complex structures that are being constructed. The growing number of projects within the urban environment also leads to readymix trucks being subject to traffic congestion while delivering – an important reason why extending the workability of concrete through admixtures is vital. 

that are applied to the surface and incorporated into the concrete skin. “During the day, the particles imitate natural aggregates, absorbing natural and artificial ultra violet radiation,” he says. “After dark, they then release the energy to give an attractive luminous glow to concrete surfaces, illuminating selected areas of a building or home. Apart from its aesthetic value, this product provides added safety for pedestrians using walkways and paths at night.” This offers exciting new design possibilities for architects, landscapers and homeowners, enhancing architectural lines of an urban building at night, or highlighting a domestic terrace or the edges of a swimming pool. The particles are available in four colours, and the intensity of the illumination can be adjusted by changing the volume of particles on the concrete skin. The LuminTech range is durable and environmentally friendly, resisting both impact and friction. It is also sourced from composite recycled material and natural mineral pigments, making it suitable for projects that focus on sustainability. Decorative concrete In another step that has enhanced Chryso’s offering in decorative concrete, the company recently acquired French company Moderne Méthode – a global leader in stamped, polished and micro- topping concrete, millimetric coatings (with different aspects such as stabilised-sand, granite, marble and metallised effect), as well as resins and stampable overlays. It also acquired the Béton Academy, with its highly technical modules to guide this new craft of decorative concrete applicators. The academy boasts 11 training centres and is ISO 9001 certified. Sustainability Sustainability and cost effectiveness remain priorities among contractors and the ready availability of pulverised fly ash (PFA) from power stations in South Africa has led to the widespread use of extended cements.

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CONSTRUCTION WORLD NOVEMBER 2017