Abstract:
The dissertation focuses on the use of secondary raw materials (SRMs) in binary cementitious self-compacting systems containing CAC and OPC to modify their response. Applications of such systems are demonstrated for rapid structural repairs works and sometimes making them as pre-placed aggregate concrete (PPAC) systems. Suitable blends of limestone powder (LSP) and Class F Fly ash (FA) in multiple binder systems containing OPC and high alumina cements were studied and tested using ambient and adiabatic curing regimes to study conversion-based strength degradation of self-compacting grout systems employing CAC. This research gives useful data on flow, strength and microstructural development employing different curing regimes, cement fineness and lime content on the response of respective self-compacting systems. Microstructural studies revealed that hardened state density and early strength behavior of the hydrated paste systems is dependent on growth and evolution of main reaction products and their derivatives. Replacing OPC by 20 % CAC delayed the formation of Portlandite as indicated by XRD results. The synergetic effect of FA and LSP’s in OPC-CAC self-compacting grout systems resulted in ettringite-phase stabilization due to the formation of Mono-carboaluminates. For such systems the gradients of shrinkage response became gentle by almost 68 % and ensured some volume stability in the system. Finally, incorporation of FA and LSP to OPC-CAC systems minimized conversion-based-reduction in strength values from 30% up to 111% and resulted in the almost full recovery of compressive strength for the studied systems.
