Effect on Key Properties of Self-Compacting Concrete Produced by Using Cementitious Materials, Ultrafine Concrete Additives and Fourth Generation Super-Plasticizers

Abstract

Self-compacting concrete (SCC) is a flowing concrete that does not require vibration and, indeed, should not be vibrated. Many researchers have adopted different methods for achieving compatibility of SCC till the date.High flow-ability is vital criteria for the application of SCC in construction practices. In this experimental program, high grade SCC mixes were established & evaluated the properties of fresh concrete as well as hardened concrete. M-70 grade at 45 days is targeted with initial strength 3 days (40%) & 28 days (80%). i.e 60 N/mm2 at 28 days. Mixes were prepared by using combinations of cementitious materials – OPC & PFA, hycrete, Metakaolin and fourth Generation Super-plasticizers admixture pure Polycarboxylate ether (PCE base). First of all, optimized percentage doses of hycrete were fixed and same percentage was used for next trials. Criteria for percentage of optimization for hycrete is mainly based on cohesiveness, flow, retention & the strength parameters of initial i.e 3/7 days & 28/45 days. Water to binder ratio and chemical admixture dosage were kept constant i.e 0.26 & 0.65% respectively, for all trials. Initial flow of SCC was observed along with flow at 60 minutes, 90 minutes & 120 minutes intervals.The primary aim of this study is to investigate the effect on key properties of Self compacting concrete by four different types of cementitious materials ((blended concrete) such as OPC & PFA, hycrete, Metakaolin and fourth Generation Super-plasticizers admixture pure Polycarboxylate ether (PCE base). This paper has highlighted the effects on properties of fresh SCC such as flowability with desired retention as well as hardened properties like Compressive strength. In this study our main focus is to investigate the effect on flow ability & retention period as well as compressive strength for initial & later age phase of concrete. The results shows overall improvement in workability, minimum two hours retention period, targeted gain in early age as well as later age compressive strength of SCC was observed. Early age desired strength is essentially required for stripping of modern forms like Aluminum shuttering & later age strength is essential for desired concrete grade.

Keywords: Self compacting Concrete (SCC), Polycarboxylate ether (PCE), Ordinary Portland Cement (OPC), Pulverised Fly Ash (PFA)