Laboratory Evaluation of a Chemical Technique to Determine Water and Cement Content of Fresh Concrete


Book Description

The report presents information obtained from laboratory evaluation of a chemical procedure for determining the water and cement content of a concrete in the plastic state. The procedure uses chloride ion titration to determine water content, and flame photometry (calcium signature) to determine cement content. This study evaluated the procedure to determine if it could be used to estimate concrete strength potential and to define to what extent test results are influenced by aggregate type, aggregate moisture conditions, aggregate absorption capacity, concrete mix proportions, mix time, and time of sampling. Results indicate that the procedure can rapidly (approximately 15 minutes) determine the water and cement content of fresh concrete and that it can be used to predict strength potential with an accuracy equal to that of predicting strength from known mix proporations. (Modified author abstract).




Evaluation of a Chemical Technique to Determine Water and Cement Content of Fresh Concrete


Book Description

This report presents information obtained from an evaluation of a chemical procedure for determining the water and cement content of a concrete in the plastic state. The procedure uses chloride ion titration to determine water content, and flame photometry (calcium signature) to determine cement content. This study evaluated the procedure to determine if it could be used to estimate concrete strength potential and to define to what extent test results are influenced by aggregate type, aggregate moisture conditions, aggregate absorption capacity, concrete mix proportions, mix time, and time of sampling. The field worthiness of the system was also evaluated.







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 w







Evaluation of Selected Procedures for the Rapid Analysis of Fresh Concrete


Book Description

Presented in this paper are results of a program to evaluate procedures for the rapid determination of both cement and water contents of fresh concrete. Three generations of a general method were considered. The abilities of the current (Generation II-Construction Engineering Research Laboratory/Kelly Vail [CERL/KV]) and recently evolved (Generation III-Construction Engineering Research Laboratory/Concrete Quality Monitor [CERL/CQM]) procedures to aid in predicting cement and water contents of a variety of concrete mixtures were determined in an extensive series of side-by-side laboratory tests. Evaluated in the tests were effects of sampling techniques and aggregate type. Analysis of variance techniques were used as aids in establishing accuracy statements and comparing the two procedures. Results demonstrated that accuracies of the CERL/KV and CERL/CQM methods were equivalent for identical test conditions. Further, it was determined that aggregate characteristics affect results of both cement-content tests and both water-content tests.




Evaluation of the Troxler Model 4430 Water-Cement Gauge


Book Description

Prepared by the Highway Innovative Technology Evaluation Center, a CERF Service Center. This report describes a HITEC evaluation designed to determine the basic capabilities and limitations of the Model 4430 gauge, manufactured by the Troxler Electronic Laboratories,Øfor use in quality control and quality assurance procedures for concrete construction. The ratio of water to cementitious materials in a concrete mix is recognized as a prime determinant of the strength and ultimate durability of the concrete. The Model 4430 Nuclear Water/Cement Ratio Gauge is designed to measure the water-to-cement ratio in fresh concrete sequentially. The evaluation was carried out in four phases: computer simulations, laboratory testing,precision and bias evaluation, and field demonstrations.




Fresh Concrete


Book Description

Fresh concrete is generally featured in publications on concrete technology where the focus is often on fundamental rheology or diverse research methods, or the standards describe the tests but do not provide practical advice on interpretation of the results. This book aims to fill the gap between highly scientific and fundamental works and the many fragmented test specifications. It summarises the existing knowledge on the properties of fresh concrete in a form accessible to practicing engineers and concrete technologists. It includes a manual of practical tests which cover both the standard tests in major countries and new tests specifically applicable to site testing. The testing equipment required and the procedures are described in sufficient detail for the tests to be carried out, with references to selected national standards when compliance with specific conditions applicable in those countries is required. Particular attention is paid to properties of special fresh concrete mixes which are increasingly used in practical construction. The work will be of interest to engineers and others involved in the research, development, design and execution of concrete construction, including those working in EEC countries.