Durability and microstructure studies on Slag-Fly Ash-Glass powder based alkali activated pavement quality concrete mixes

Abstract

The present study attempts a detailed assessment of the performance of air-cured Alkali Activated Concrete (AAC) mixes produced using powdered waste glass as one of the ingredient, designed for highway applications. In this current investigations, the alkaline solution is prepared using sodium hydroxide flakes and liquid sodium silicate solution. Initially, AAC mixes are designed to obtain a pavement quality concrete (PQC) of grade M−45 using Ground Granulated Blast Furnace Slag (GGBS) and fly ash (FA) as binding ingredients in ratios of 75:25, incorporating graded crusher dust as fine aggregates. Based on the preliminary investigations, the design Na2O dosage of 4% and the modulus of activator (Ms) = 1.25 was selected and this dosage was maintained for the extended investigations. The further investigations were carried out for various trial dosages of waste glass powder (GP) in the concrete mix. The selected AAC mixes were tested with compressive and tensile strengths, flexural strength, unit weight, modulus of elasticity, durability properties (i.e, prolonged strength, acid attack, sulphate attack, and saline water attack tests); the microstructure studies using SEM with EDAX and the obtained results were discussed. The study reveal that, the AAC mixes display satisfactory performance for normal working environments for their use in roadway appliances. Thus, the use of AAC mixes produced using GGBS-FA-GP in association with the graded crusher dust fine aggregates is considered to be an economical and eco-friendly alternative to use of conventional concretes for highway applications.