Research and application

New developments in admixtures for precast and readymix concrete

Chemical admixtures have impacted modern concrete technology more than any other development from the last 30 years. Most notably, the introduction of polycarboxylate (PCE) superplasticizers, viscosity-modifying agents, early strength enhancing (seeding) admixtures and self-healing agents present substantial technological break-throughs which for the first time allow us to formulate concrete exhibiting extremely long slump retention (6+ hrs), very high early strength at no sacrifice for final strength, ultra-high strength concrete (UHPC), self-compacting and self-levelling concrete (SCC), self-healing concrete and extremely durable concrete. In this paper the properties of these admixtures are described. Furthermore, technology gaps existing in the field of admixtures are identified and an outlook into potential future developments is given.