Author ORCID Identifier

0000-0002-4688-3852

Date of Award

17-8-2025

Document Type

Thesis

School

School of Civil Engineering

Programme

Ph.D.-Doctoral of Philosophy

First Advisor

Dr.K.Parthiban

Keywords

One Part Alkali Activated Concrete, Rice Husk Ash, Waste Glass Powder, Sustainability Mechanical And Durability Properties

Abstract

The environmental concerns associated with the traditional ordinary Portland cement (OPC) such as CO2 emission and high energy demand along with resource depletion as binder has led to the development of alkali activated binders (AABs). Even with the reduction in environmental issues, the implementation of AAB in practice is hindered by the handling issues of liquid activators. Hence, it is required to develop AAB with powdered activators to address the handling issues and to further reduce the environmental issues related to the production of activators. This research investigates the development of one-part alkali-activated concrete (OAAC) system utilising wastederived materials as alternative activators.

The core of this study lies in the synthesis of powder activators through a mechanothermal process involving the combination of rice husk ash (RHA) and waste glass powder (WGP) with sodium hydroxide (NaOH) in six distinct ratios with ground granulated blast furnace slag (GGBFS) as precursor. The developed OAAC mixes were evaluated for its fresh, mechanical, durability and microstructural properties. The compressive strength of OAAC mixes achieved its peak value of 56.27 MPa and 59.12 MPa for RHA- and WGP-based activators respectively.

Similarly, the OAAC mixes developed with RHA-based activators achieved a maximum split tensile strength and flexural strength of 4.64 MPa and 6.25 MPa respectively, whereas mixes with WGPbased activators recorded 5.26 MPa and 6.12 MPa respectively. In terms of impact resistance, the initial cracking impact number increased by 7.9 to 10.5 times and 6.2 to 8.9 times respectively for RHA- and WGP-based mixes with 1% fibres compared to nonfibred mixes. Similarly, mixes with 1% fibre yielded the maximum fracture toughness with an improvement of 18.1% and 16.3% for RHA- and WGP-based mixes respectively. In addition, the developed OAAC mixes showed excellent durability characteristics than the conventional mixes.

The formation of amorphous aluminosilicate gel and semicrystalline phases identified from the SEM and XRD analyses show that the derived activators enhance bonding and reactions with the aluminosilicate precursor in OAAC, resulting in a strong microstructure with reduced porosity and enhanced mechanical and durability properties.

OAAC mixes developed with RHA- and WGP-based activators results in a significantly reduced CO2 emission by 62.4% and 63.5% respectively than cement concrete mix. With the improved mechanical and durability properties alongside sustainability indicators, the findings pave way for future innovation in green construction materials, offering a viable pathway toward reducing the carbon footprint from the construction sector while addressing the global issue of industrial waste management.

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