Investigation of treated Incinerated Bottom Ash (IBA) as fine aggregate replacement in structural concrete – from waste to construction material

Low Shi Li, Samuel (2025) Investigation of treated Incinerated Bottom Ash (IBA) as fine aggregate replacement in structural concrete – from waste to construction material. MSc(R) thesis, University of Glasgow.

Abstract

With the shortage of sand and its ever-increasing needs for urbanisation due to concreting, researchers have been seeking alternative materials to replace natural sands in concrete. Among the potential fine aggregate alternatives is the cement-treated Incinerated Bottom Ash (IBA), which is a granular byproduct of incinerating municipal solid waste. However, leaching of hazardous substances from untreated IBA is a major issue that hinders its usage in engineering applications. In this study, treated IBA (GO-IBA™) was adopted, where the pollutants are encapsulated within the pellet structure, hence reducing the leaching of hazardous substances.

This work aims at experimentally investigating the effects of replacing natural fine aggregates in structural concrete with treated and untreated IBA on fresh properties, hardened properties and durability. Secondly, in order to reduce the reliance on natural sands, the performance of concrete mixes using manufactured sand with IBA replacement is also assessed. Moreover, to further bring down the CO2 emissions during concrete production, the feasibility of replacing fine aggregates with IBA in concrete using blended cement is also experimentally studied.

Accordingly, experimental investigations on four series of speimens were carried out: (1) C Sand mixes with rIBA – untreated IBA (rIBA) replacing natural sand (C Sand) with OPC as binder, (2) C Sand mixes with GO-IBA™ – treated IBA replacing C Sand with OPC as binder, (3) M Sand mixes with GO-IBA™ – treated IBA replacing manufactured sand (M Sand) with OPC as binder, and (4) PBFC mixes with GO-IBA™ – treated IBA replacing M Sand with CEM III/B cement as binder. In each test series, fine aggregate replacement levels were set at increments of 25% to study the effects better. Different test are employed to study the individual concrete properties which are categorised into three main properties: (1) Fresh properties (slump, bleeding, setting time and air pore content), (2) Hardened properties (compressive strength test and modulus of elasticity (MOE) test) and (3) Durability properties (water penetration (WPT), water absorption (WAT), rapid chloride penetration test (RCPT) and accelerated carbonation test.

The test results show that using untreated IBA to replace fine aggregates leads to inferior workability, significantly reduced mechanical properties and degraded durability, making it not suitable as a fine aggregate replacement for structural concrete.

When using treated IBA as the fine aggregate replacement (for both C Sand mixes and M Sand mixes), the workability still tends to reduce with the replacement level, possibly due to the porous nature and high water absorption properties of GO-IBA™, while the compressive strength exhibits insignificant reduction till 75% replacement level. In terms of durability, both the C Sand mixes and M Sand mixes with treated IBA replacement show improved water penetration depths till 75% replacement level and better RCPT and accelerated carbonation test results till 100% replacement level. Nevertheless, increasing the treated IBA replacement level leads to higher water absorption, which affects the workability of the mix and yields higher air pore content. In this work, it is also found that pre-wetting of the GO-IBA™ results in improved workability and compressive strength development.

In the last series of the test, with the addition of Ground Granulated Blast furnace Slag(GGBS) as the binder, most of the fresh properties were improved over the cement counterparts (M Sand mixes), except for the delayed setting time due to the longer hydration time involving GGBS. Hardened properties of the PBFC mixes with GO-IBA™ remain broadly similar in trend to the cement counterpart. In terms of durability, the WAT and WPT results exhibit degraded performance compared with the cement counterparts, due to the longer hydration time needed for GGBS. RCPT results remain similar in trend, while accelerated carbonation test results show poorer performance than the cement counterparts.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Keywords: Cold-bonded palletisation, waste, incinerated bottom ash, concrete, aggregates replacement.
• Subjects: T Technology > TA Engineering (General). Civil engineering (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Liang, Dr. Yating and Grassl, Dr. Peter
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85602
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 21 Nov 2025 16:00
• Last Modified: 21 Nov 2025 16:01
• Thesis DOI: 10.5525/gla.thesis.85602
• URI: https://theses.gla.ac.uk/id/eprint/85602