Inland Branch Technical Seminar: Essentials for Successful Concreting – Nelspruit
For the first time, the Inland Branch of the Concrete Society presented one of its technical seminars to members and visitors in Nelspruit, Mpumalanga.
This proved to be a very popular initiative with almost 60 people gathering to listen to the latest developments in concrete technology, concrete testing and standards and specifications.
Roelof Jacobs, Chairman of the Inland Branch welcomed the delegates to the meeting and confirmed that the visit by the Society to Nelspruit was part of a new strategy to reach out to the professions in areas outside of the main metropolitan centres. In this way, he said, we hope to grow our membership and at the same time contribute to our overall objective of promoting excellence in the design and use of concrete.
Proceedings began with a presentation by Bryan Perrie, MD of The Concrete Institute, on the latest amendments and refinements to the current South African concrete standards. He confirmed that three design codes were currently under review, namely:
- Loading code and basis of design (2010)
- Concrete water retaining standard
- Concrete design standard
He continued by describing in some details the progress being made by the various committees in bringing changes to these codes to fruition.
Bryan then talked about specifying concrete and the move away from the traditional prescriptive approach with performance requirements, towards a new philosophy of determining the environment and required longevity, required durability, the approach to achieving that durability and then determining the structural design.
With this detailed presentation of current changes to standards and specifications for concrete, including construction, materials and test methods, delegates received the very latest on this important topic.
Next to present was Johan van Wyk, GM of the SARMA and Vice-Chairman of the Inland Branch.
Johan covered the importance of testing concrete in the quest to achieve a consistently high-quality end product. There were challenges he suggested with cement quality being regulated, concrete having specifications, but nothing governing its quality. He suggested that there should be a ‘law’ controlling concrete quality.
The various tests governing materials used in the production of concrete were covered, including cement, aggregate, sand, water and chemicals admixtures. Given that all these were done to the satisfaction of the producer, trial mixes should still be carried out to verify mix design, Johan asserted.
Moving on to the concrete itself Johan described the various tests that should be carried to ensure a consistently good, quality concrete, including slump (for workability); flow; strength; air content; wet density and setting times.
He concluded his presentation with a quotation form John Steinbeck – “I am compelled, not to squeak like a grateful and apologetic mouse, but to roar like a lion out of pride in my profession”.
The final speaker was George Evans, Technical Specialist with PPC, who presented and entertained in his own inimitable style. He focused his presentation on factors influencing test results. He considered inspection and testing plans, acceptance criteria, reference documents, and material and concrete sampling.
He went on to say that testing can be influenced by such factors as temperature, time, equipment used, and skill/experience of the tester. Several examples of the results of bad testing techniques and/or ignorance of the correct testing procedures, were shown.
In conclusion, George challenged the audience by asking what they had learnt from the presentation. He suggested that they should now know more about the factors that influence test results, i.e.
- Sampling – frequency, method, size
- Environment – access, ambient conditions
- Equipment – conformity, maintenance
- Understanding principles – training
In closing the seminar, Roelof Jacobs thanked the delegates for their attendance, and also PPC for their generous sponsorship of the event.