Development of a sustainable high early strength concrete incorporated with pozzolans, calcium nitrate and triethanolamine: An experimental study

Abstract

High early strength concrete is a high-performance concrete that achieves a compressive strength of at least 20 MPa in 24 h. High early strength concrete becomes sustainable when pozzolans are incorporated. The best way to achieve sustainable high early strength concrete is the addition of chemical accelerators and pozzolans to conventional concrete. In this study the combination of 1 % calcium nitrate and 0.05 % triethanolamine is used as chemical accelerators. Three different types of Sustainable high early strength concrete are prepared: Ordinary portland cement with accelerators, Portland slag cement with accelerators, and ordinary portland cement replaced by 15 % Metakaolin with accelerators. The mechanical properties are determined through compressive strength, split tensile strength, and flexural strength. Durability performance was evaluated using rapid chloride permeability, water permeability, sorptivity, ultrasonic pulse velocity, sulphate resistance, chloride resistance, and acid resistance from day one to 270 days. In addition, characterization and microstructure analysis were studied using Scanning Electron Microscopy, Energy-Dispersive X-ray spectroscopy, and X-ray diffraction under chemical curing conditions. The experimental outcomes revealed that ordinary portland cement concrete substituted with 15 % Metakaolin and accelerators achieve early strength and durability performance, compared to ordinary portland cement with accelerators and Portland Slag Cement with accelerators.