Testing During Concrete Construction


Book Description

Testing concrete while construction is underway enables decisions to be made which can improve the quality of the finished structure. The book covers testing and measuring techniques for fresh concrete and concrete during the first few days after placing, and for reinforcement and prestressing tendons. Many examples are given of practical methods which can be applied directly during concrete construction to improve quality. It forms the Proceedings of the International RILEM Workshop in Mainz, Germany, March 1990.










Ultrasonic Testing to Determine Water-Cement Ratio for Freshly Mixed Concrete


Book Description

The objective of the research presented here was to find promising directions for the development of ultrasonic test method(s) for the direct, instantaneous determination of the water-cement ratio (W/C) in fresh mortar or concrete. The importance of W/C is related to potential strength development and, to a certain extent, the durability potential of the hardened concrete. Since previous efforts during the past 50 years have been unsuccessful in testing fresh concrete due to the complexity of the problem, innovative, high-risk/high-gain methods were selected in the present work. The methods are considered innovative since a literature search detected no sign that they have been used for testing fresh concrete before.




Non-Destructive Evaluation of Reinforced Concrete Structures


Book Description

Many concrete structures and elements of concrete infrastructure have exceeded their original design lives and are deteriorating to an extent where they are becoming dangerous. The deterioration can be internal or not obvious and therefore only shows up with detailed testing. Non-destructive evaluation of reinforced concrete structures, Volume 1: Deterioration processes and standard test methods reviews the processes of deterioration and classical and standard test methods.Part one discusses deterioration of reinforced concrete and testing problems with chapters on topics such as key issues in the non-destructive testing of concrete structures, when to use non-destructive testing of reinforced concrete structures, deterioration processes in reinforced concrete, modelling ageing and corrosion processes in reinforced concrete structures, components in concrete and their impact on quality, and predicting the service life of reinforced concrete structures. Part two reviews classical and standard testing methods including microscopic examination of deteriorated concrete, the analysis of solid components and their ratios in reinforced concrete structures, the determination of chlorides in concrete structures, and investigating the original water content of reinforced concrete structures.With its distinguished editors and international team of contributors, Non-destructive evaluation of reinforced concrete structures, Volume 1: Deterioration processes and standard test methods will be a standard reference for civil and structural engineers as well as those concerned with making decisions regarding the safety of reinforced concrete structures. - Provides a comprehensive discussion from examination of the components in concrete and their affect on quality through to the role of and tools required for lifetime management - Experts in the field identify the testing problems associated with infrastructure considering design, build and maintenance stages - Presents a guide for when to use non-destructive testing of reinforced concrete structures including the role of time in testing













Development of a Water-Cement Ratio Meter


Book Description

The objective of this project was to develop a water-cement ratio measurement meter for easy, rapid and reliable use in the field. The goal was that the equipment be portable, easy to use, low cost and low maintenance, and be able to provide consistent and accurate results. A prototype device has been developed to measure the water-cement ratio of a plastic concrete mix. The method is based on the turbidity of water-cement slurry separated from a concrete mixture by "pressure sieving". Consistent results were obtained for both air entrained and non-air entrained concrete. Statistical analyses of the test results have shown that the Kansas Water-Cement Ratio Meter can measure the water-cement ratio of fresh concrete with an accuracy of +/-0.01 with 90% confidence. The test time is less than 10 minutes which includes cleaning the equipment. Further evaluation with admixtures, and under field conditions are planned