Housing in Southern Africa July 2016

Cement & Concrete

Quality concrete on site

Johan van Wyk

Guinevere Thomas “This is all part of Sarmamembers being proactive and adding value. The contractor may or may not be aware of the importance of effectively specifying concrete,” explains Johan van Wyk, Sarma General Manager. “As a progressive industry it is our job to enlighten our customers and ensure that apart from the basics, they also get concrete that is easy to work with, appropriate for the task and is tailor made. For example, if the concrete has to be transported long distances on site via wheel barrow, the ready mixer may need to retard setting a little in order to allow time to place the concrete, etc.” He says, “There are many other Mariana Lamont A ll Southern Africa Readymix As- sociation (Sarma)members are required to have the necessary knowledge and correct processes in place to manufacture concrete, ac- cording to strict criteria. In addition, they have access to technical knowledge that allows them to manipulate mixes to meet the customers requirements. Sup- pliers are also in a position to advise on the required properties and best mixes to get the job done, quickly and efficiently.

Apart from basic strength and slump parameters, contractors can make use of the knowledge that readymix suppliers can provide in terms of ease of delivery to the required point, concrete placement and workability.

least five minutes on site before dis- charging. Upon discharge ensure that all requirements on site are in place (rebar has been inspected, formwork inspected, etc.) and that necessary testing be done according to agreed methods by nominated persons. Upon placement ensure that compaction is done correctly (to get the air out) and that protection and curing methods are put in place im- mediately. He advises that communication is critical with all parties on site and that ready mix staff be consulted to ensure that everything is going ac- cording to plan. “As long as these basics are in place, the readymix company canpre- pare mixes in accordance with these requirements. On site, cooperation and communication will make the jobmuch easier,” concludes vanWyk. For further information con- tact Sarma on 011 791 3327 or visit www.sarma.co.za ■

‘tricks’ that can be used to make placement easy, save time andensure the highest strength and quality. It’s all about communication and ensuring that the readymix supplier understands each and every param- eter of the usage of the concrete on site. A Sarma accredited supplier will be able to add far more value than merely sticking to a strength and slump specification,” says van Wyk. He recommends the following cri- teria be discussed with the concrete supplier upfront in order to draw up an adequate specification: strength requirements; workability require- ments; application (know where it is being used i.e. structural column, floor etc.); location (address, coordi- nates, which entrance, details etc.); contact person; time required on site; access requirements; and site trans- port (wheel barrows, pump, bucket etc.) On receiving concrete van Wyk suggests that all the resources be ready and that the truck spins for at

July 2016