Properties and TestsBy
- P. Bartos, Paisley College, Paisley, Scotland, UK
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.
Developments in Civil Engineering
Published: July 1992
- 1. Introduction.Concrete as a composite material. Fresh concrete in construction practice. References. 2. Basic Rheology. Application to fresh concrete. Newtonian flow. Non-Newtonian fluids and coarse suspensions. 3. Fresh Cement Paste. Fresh paste in concrete. Microstructure and rheological characteristics. Factors influencig the consistency of cement pastes. Properties of cement and the hydration process. Mixing procedure. Other factors. Test methods and interpretation of their results. Rotational viscometry. Penetration tests. References. 4. Fresh Concrete Mix. Basic terms and characteristics used in technology of fresh concrete. Workability and consistency. Mobility and pumpability. Stability, segregation, bleeding. Compactability. Finishability. Test methods. General requirements. Sampling of fresh concrete. Practical workability tests: slump. VeBe. spread / Flow table. Compaction factor. Compaction (Walz). Flow (L.C.L.). Kelly Ball. Orimet. K-Slump. Visual assessment. Air content: Pressure method. Gravimetric method. Volumetric method. Density and unit weight. Temperature. Principal factors affecting workability of ordinary fresh concrete. Types and properties of aggregate: Size and grading. Shape and texture. Density. Moisture content. Types and properties of cement. Mix proportions. Mixing procedure. Time and temperature. Vibration. 5. Admixtures. Workability agents. Ordinary plasticizers. Superplasticizers. Air-entraining agents. Agents affecting setting and hardening. Accelerators. Retarders. Colouring agents. Other admixtures. Gas generating and foaming admixtures. Admixtures for underwater concreting. Mineral admixtures. Thickening and thixotropic admixtures. Polymers. Shrinkage compensating and expanding admixtures. Integral waterproofing admixtures. 6. Cement Substitutes. Pulverised fuel ash (Fly Ash, PFA). Plasticizers and superplasticizers. Air entrainment. Ground granulated blastfurnace slag. Microsilica (Condensed silica fume). 7. Fibres. Glass fibres. Applications. Basic fibre properties. Basic matrix properties. Properties of a fresh GRC mix. Steel fibres. Types of fibres. Assessment of workability of fresh SFRC mixes. Polymer fibres. Other fibres. 8. Analysis Of A Fresh Mix. Rapid analysis (RAM) test. Other methods. Buoyancy method. Pressure filter method. Chemical method. Physical separation method. Appendix. Glossary of Terms. Author Index. Subject Index. (An Introduction and References are included with each chapter.)