Civil Engineering April 2021 | Vol 29 No 3

Civil Engineering April 2021 59 The guide notes that, although Africa remains one of the fastest-growing conti- nents, growth is expected to be moderate. The implementation of sound macro­ economic policies has meant that Africa’s economies have generally remained resil- ient. Countries such as Ethiopia, Ghana and Côte d’Ivoire are three of the fastest- growing economies globally in terms of increased GDP. Africa’s growth is further bolstered by several East African coun- tries contributing collectively through increased exports and cross-border trade to boost regional growth. There is an ever-growing need to finance infrastructure on the continent. Several countries are now prioritising this after realising the importance of industrialisation to maintain growth in their economies but also recognising the need to diversify through the exporta- tion of goods and services. This has consequently created the jobs needed for a burgeoning younger population. A developing industrial sector on the continent requires more infrastructure investment, particularly in power, water, and transportation services, which are already over-stretched. An increased oil price and the stabilisation of commodity prices have helped strengthen the forecast for GDP growth on the continent. Predictions of collective growth are around 3% to 4% for 2020/21, with individual countries increasing by as much as 7% to 8%. Sub- Saharan Africa is seeing steady growth in the infrastructure and construction sectors, as well as in East and West Africa. Important here are the signing of mega gas deals in Mozambique following favourable environmental impact studies and subsequent government approval for parts of liquefied natural gas develop- ment contracts. This is expected to create thousands of job opportunities, significantly impact Mozambique’s GDP, and create col- laborative opportunities for neighbouring countries. “Despite the initial direct feedback from Eastern Africa indicating that the impact of the coronavirus pandemic slowed down all planning, construction and other related activity, there are grassroot signs that prioritising infrastructure and construction creates the opportunity for economies to recover,” reports Dean Narainsamy, Director: PCC Africa at AECOM.  A full grasp of concrete technology is vital for contractors Cutting corners on site could be catastrophic With the Covid-19 pandemic influencing rampant cost-cutting in the building industry, there is a growing danger of neglecting sound site practice which determines concrete performance and infrastructural safety and durability, cautions John Roxburgh, senior lecturer at the School of Concrete Technology, part of Cement and Concrete SA (CCSA). CCSA was established in March 2021 through the consolidation of The Concrete Institute, Concrete Society of Southern Africa, and the Association of Cementitious Material Producers. Roxburgh cautions that although the current economic crunch undoubtedly calls for saving costs, it should not be at the cost of site expertise. Contractors will need a full grasp of concrete technology to be able to achieve a satisfactory balance between pricing and maintaining their company’s credibility. “With good quality concrete – either batched on site or delivered there – the contractor has limited time for placing, compaction, finishing and curing. So, knowing what to expect is vital. Firstly, a good concrete practitioner should be able to assess the quality of the concrete supplied and decide whether it meets specifications or should be rejected. Then the concreting team needs to have timeously established how the concrete will be transported on site. They must also have organised and implemented placement and compaction methods and ensured that the curing system has been fine-tuned with all necessary equipment and staff standing by,” explains Roxburgh. He says there is a limited time to get concrete placed and compacted so the work needs to proceed straight away to ensure cracking potential is mitigated and that there is sufficient time to finish the concrete works. “Sound concrete site practice can only be achieved by ‘concrete wisdom’. A trained concrete team will know how to prevent segregation in the concrete, both through mix design and handling. The same applies to preventing crack forma- tion and for suitable finishing and curing of the concrete. Property-owners whose structures fail within a short period of time are not likely to entrust more work to the under-performing contractors. The cost implications are simply too important for the developers and, for the contractors concerned, such failures could mean the end of their business,” Roxburgh warns. The School of Concrete Technology’s SCT20 – Concrete Practice course (currently available as an online self-study course due to Covid-19) is a vital training tool to ensure the best site practice for concrete works. It provides trainees with essential concrete technology concepts and theoretical background to implement trustworthy and proven methods of dealing with concrete on site.