Mechanical and microstructural properties of structural and non-structural lightweight foamed concrete with coal bottom ash as cement and sand replacement material

Abstract

This study aims to assess the feasibility of including coal-bottom ash (CBA) as a substitute for cement and fine aggregate, with a replacement ratio of 20%, and 75%, respectively, in the production of lightweight foamed concrete (LWFC) at two different densities: 1300 kg/m³ and 1700 kg/m³. The study provided data on both its fresh and hardened states. These include water absorption, density, compressive, splitting tensile strength, rupture modules, modulus of elasticity, X-ray Diffraction, and Field Emission Scanning Electron Microscope. The findings indicated that including CBA as a substitute for cement and fine aggregate can yield environmentally friendly foamed concrete suitable for structural applications, exhibiting a compressive strength of up to 25.5 MPa. In addition, decreasing the CBA aggregate size in specimens with a density of 1300 kg/m³ resulted in increased strength. The mixes that included CBA contained additional C-S-H gels, which led to a more compact structure.

Keywords:

• coal bottom ash (CBA)
• cement replacement
• foamed concrete
• mechanical properties
• microstructure

Acknowledgments

The authors are grateful to University Malaya for the financial support through the Private Research Grant bearing project grant No. Ref: PV002-2019 (Development of Cellular Lightweight Concrete (CLC) Using Coal Bottom Ash (CBA).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the Institut Pengurusan dan Pemantauan Penyelidikan(IP P P), Universiti Malaya through the financial support of Private Research Grant bearing project grant No. Ref: P V002-2019 (Development of Cellular Lightweight Concrete (CLC) Using Coal Bottom Ash (CBA)) by ACE GREENCEMT PRODUCTS SDN. BHD.

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