Evaluation of early age cracking characteristics in cementitious systems

Early age cracking has re-emerged as an important issue in modem concretes, and it has its impact in developing new formulations for high strength and repair. Adequate performance with respect to cracking cannot be properly assessed on the basis of free shrinkage tests. More advanced methodologies need to be developed and applied, to consider in addition to the strains obtained also the stresses and stress relaxation. The present paper presents an overview of the testing techniques and methodologies of early age cracking. It classifies the tests into four categories: ring, plate, longitudinal and substrate restraint and assesses their significance and limitations.