Concrete Mix Design, Quality Control and Specification

Preface. Acknowledgements. Foreword by John Peyton. Foreword by Bryant Mather. Foreword by Joe D Dewar. Design of concrete mixes. Philosophy. Design criteria. Use of strength as a basis. Considerations other than strength. Selection of design strength. The cube/cylinder relationship. Flexural and tensile strength. Some historical and alternative systems of mix design. 1:2:4 mixes. Ideal grading curves. Gap gradings. Road note 4. BRE/DOE system. Manual use of Conad system. The ACI system. Trial mix methods. Dewar - particle interference and void filling. Popovics. Brusin method. RILEM Technical Committee TC 70-OMD. Assessment of alternatives. The Conad Mixtune method of mix design. Objectives of the method. Mix suitability factor (MSF). Equivalent water factor (EWF). Specific surface. Surface modulus. Particle shape. Silt content. Modified specific surface. Cementitious materials and entrained air. Temperature/time effect. Factors affecting water factor. Pozzolanic materials and slag. Overall water predictions. Fine aggregate water requirements related to void percentage and flow time. Strength considerations. Yield and unit weight. Mix variations and trial mixes. Computerization. High strength concrete. Philosophy and techniques of quality control. Historical evolution. The nature of concrete viability. Quality control techniques. Control charts. Computerization of QC methods. The Conad quality control system. Development of the system. Essential features. Comprehensive integration. Mix input. Computer batching analysis. Test date input. Test details and certificates. Multigrade, multivariable analysis. Single grade analysis. Statistical table. Integration of batching data with concrete test data. Evaluation of relative efficiency of mixes. Early-age testing. Prediction of 28-day strength. Non-destructive testing. Fresh concrete tests. A self-regulation batch plant? Specification of concrete quality. Deficiencies of existing specification techniques. Specification basis. Cash penalty specifications. Rapid reaction to unsatisfactory quality. Specification of methods, equipment and facilities. Specification of early-age strength. Proposal-approval specifications. The recommended specification. Small volume projects or plants. Summary. Appendix: An example of a cash penalty specification. Aggregates for concrete. Fine aggregate (sand). Coarse aggregate. Lightweigh aggregates. Blastfurnace slag. Cementitious and pozzolanic materials. Portland cement. Fly ash (pfa). Blastfurnace slag. Silica fume. Rice hull ash (RHA). Chemical admixtures. General. Specifying admixture usage. Possible reasons for using admixtures. Types of admixture available. Statistical analysis. The normal distribution. Permissible percentage defective. Variability of means groups. Variability of standard deviation assessment. Components of variability. Testing error. Coefficient of variation. P