Civil Engineering October 2021 | Vol 29 No 9

18 October 2021 Civil Engineering J ohn Roxburgh, Senior Lecturer at Cement & Concrete SA’s School of Concrete Technology believes it is a matter of deep concern that many key institutions – including South African municipalities and state bodies entrusted with infrastruc- tural and building developments – still have limited technical concrete knowledge on call from within their own ranks. “In every civil and construction project, concrete will always be extensively used. Concrete is relatively affordable – often costing well below R400/ton on average – and it is durable, versa- tile and suitable for many applications in different environments. But if the correct concrete practices are not followed, concrete works could become a nightmare and costing could soar totally unnecessarily,” says Roxburgh. CREATING CONCRETE SUPERVISORY SPECIALISTS Roxburgh believes concrete technology education is essential for any construction project, particularly during building slumps when the mark-ups on tenders must be drastically reduced and leave little to no margin for error should unexpected mishaps occur on site. Roxburgh therefore recommends that employers identify suitable people on their staff and “champion” them to become their concrete supervisory specialists. “Site control is vital to getting concrete works done correctly and on time. Sound concrete technology knowledge at super- visory level will ensure that concrete works run smoothly. The skills required to transport, place, compact and cure concrete should be taught and controlled by a competent supervisor who has had proper training. He or she would spot potential problems at an early stage, facilitate good concrete practice and produce a quality concrete product,” he says. “Without staff with training in concrete technology so many things could go wrong on site. Plastic shrinkage, settlement and thermal cracking, blow holes, honeycombing, drying shrinkage cracking, dusting, streaking, discolouration, inadequate compac- tion, strength and curing, high permeability, cold joints, loss of cover, and lack of abrasion resistance are just a few potential problems. All we see repeatedly when visiting sites, and yet they are all easily preventable with basic concrete technology knowledge.” Roxburgh says that, in a lifecycle analysis of a structure, maintenance and repair are major contributors to the overall cost of the structure. “This is where a detailed knowledge of concrete technology will enable a professional to build a cost-effective, du- rable and low maintenance building according to its location and environment. Neglecting this will lead to escalating costs later and a structure with huge maintenance demands. Property and infrastructure owners with access to a professional with extensive concrete technology knowledge have a distinct advantage when it comes to lifetime costing.” In recent years, the importance of concrete durability has become paramount. Specifications for durability are now being written into South Africa’s national standards and many state institutions are insisting on durable concrete structures. The many South African municipalities lagging with the implementa- tion of durability requirements are probably without suitable concrete expertise in their employ, he feels. Roxburgh advises that when selecting a training provider, it is important to ensure that the provider is experienced in providing up to date, relevant concrete technology education. The training provider should also issue certificates that are well recognised within the concrete and related industries. Municipalities and government bodies need trained concrete technologists Spotting potential problems, facilitating good concrete practice and producing a quality concrete product can only be done with adequate training. Concrete forms part of infrastructure all over Africa, from low-cost housing to multi-billion-rand dams