Hardened Properties Of Self-compacting Concrete Research Articles

Combined Effect of Ternary Blended Cementitious Materials in Self-compacting Concrete

Self Compacting Concrete (SCC) is a type of special concrete which possess self packing and flowability to fill the formwork space completely by its own weight without any external vibration or compaction. Research studies on finding efficient, economical and eco-friendly materials to replace the conventional concrete materials are increasing day-by-day. An important constituent material of concrete is cement which contributes to the environmental hazardous problem of CO2 emission. In this view, the present study investigated the fresh and hardened properties of SCC in which cement is partially replaced by multi-cementitious materials namely fly ash, alccofine and Recycled Concrete Powder (RCP). Fly ash and alccofine are evident materials to replace cement in concrete. In addition to the substitution of cement by 20% replacement by fly ash and 10% replacement by alccofine, recycled concrete powder collected from construction wastes are also incorporated (5%, 10%, 15%, 20%) and investigated. Water/binder ratio is kept constant as 0.45. Polycarboxylate based super plasticizer (Conplast SP430) was used. The experimental program comprises testing the fresh stability by determination of flowability, passing ability and viscosity, mechanical strength testing including compressive strength, split-tensile strength and flexural strength and durability properties such as water absorption, sorptivity and acid-attack of SCC specimens. The test results showed that 10% recycled concrete powder exhibited better performance in fresh stability and satisfied performance mechanical strength. Increase in RCP content beyond a limited proportion possesses detrimental effects on the durability characteristics.

Plastic viscosity based mix design of self-compacting concrete with crushed rock fines

With the increasing demand in the production of concrete, there is a need for adopting a feasible, economical and sustainable technique to fulfill practical requirements. Self-Compacting Concrete (SCC) is one such technique which addresses the concrete industry in providing eco-friendly and cost effective concrete. The objective of the present study is to develop a mix design for SCC with Crushed Rock Fines (CRF) as fine aggregate based on the plastic viscosity of the mix and validate the same for its fresh and hardened properties. Effect of plastic viscosity on the fresh and hardened properties of SCC is also addressed in the present study. SCC mixes are made with binary and ternary blends of Fly Ash (FA) and Ground Granulated Blast Slag (GGBS) with varying percentages as a partial replacement to Ordinary Portland Cement (OPC). The proposed mix design is validated successfully with the experimental investigations. The results obtained, indicated that the fresh properties are best achieved for SCC mix with ternary blend followed by binary blend with GGBS, Fly Ash and mix with pure OPC. It is also observed that the replacement of sand with 100% CRF resulted in a workable and cohesive mix.