ADMIXTURES: ENHANCING CONCRETE PERFORMANCE

Superplasticizers are the most important admixtures enhancing concrete performance. The development of new superplasticizers during the last decades has determined the most important progress in the field of concrete structures in terms of higher strength, longer durability, lower shrinkage and safer placement particularly in elements with very congesteded reinforcement. The progress from sulphonated polymer to polycarboxylate has resulted in higher water reduction at a given workability and lower slump loss. More recently poly-functional superplasticizers have been developed which are able to completely keep the initial slump for at least 1 hr without any retarding effect on the early strength. Moreover, multi-purpose and poly-functional superplasticizers have been invented which are able to reduce drying shrinkage.

• INTRODUCTION

• WHY SUPERPLASTICIZERS ARE IMPORTANT

• THE PROGRESS IN SUPERPLASTICIZERS

• MECHANISMS OF ACTION OF SUPERPLASTICIZERS

• PROGRESS IN SLUMP RETENTION

• CONCLUSIONS

• REFERENCES