Every structure has its requirements with respect to strength, appearance, durability, serviceability and to meet these requirements appropriate steps must be taken at all the stages of design, analysis, construction, inspection and maintenance. The properties of concrete are often related to the strength of test specimens at 28 days. However, strength tests give no information about the real concrete in the structure, such as the materials used, the mix design, compaction or curing. Yet the surface of concrete has a crucial influence on a structure's performance. Testing during construction has clear benefits: - the quality of the work can be checked at a time when the building process can still be changed in order to improve the end product. - the effect of changes in construction processes can be assessed. - decisions can be taken on the basis of valid information. Numerous disputes arise from the fact that the materials and mix proportions are not known, and from doubts about the cover to reinforcing steel.
Testing of concrete during construction helps to assess and improve the quality of structures, to reduce overall costs, and to demonstrate the industry's concern to achieve high quality structures. This book covers testing and measuring techniques for fresh concrete, early-age concrete, reinforcement and prestressing tendons, especially non-destructive techniques. Accuracy, sensitivity, reliability and ease of use of the test methods are discussed and backed up by practical examples. Many examples are given of practical methods which can be applied directly or which suggest directions of future developments. This book forms the Proceedings of the International RILEM Workshop in Mainz, Germany, March 1990.