Effect of Partial Replacement of GGBFS by Metakaolin and Silica Fume on Mechanical and Durability Properties of Lightweight Geopolymer Concrete | ||||
Engineering Research Journal (Shoubra) | ||||
Articles in Press, Accepted Manuscript, Available Online from 22 July 2025 | ||||
Document Type: Research articles | ||||
DOI: 10.21608/erjsh.2025.375121.1405 | ||||
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Authors | ||||
Ola Naeem El-far ![]() ![]() | ||||
1Farco Engineering for Construction and Rehabilitation, Cairo, Egypt | ||||
2Department of Civil Engineering, Faculty of Engineering at Shoubra, Benha University, Egypt | ||||
3Department of Structural Engineering, Faculty of Engineering, Cairo University, Cairo, Egypt | ||||
Abstract | ||||
This work is a part of the scientific research efforts to develop cementless alkali-activated lightweight geopolymer (LWGC) concrete using granulated blast furnace slag (GGBFS) as binder, with expanded polystyrene EPS and pumice combined as lightweight coarse aggregate. This paper aims to examine the effects of partial replacing of GGBFS by silica fume (SF) and metakaolin (MK) with percentages of 10%, 20% and 50%. The effect of binder type and replacement percentage has a significant impact on the density and mechanical properties of LWGC. The mechanical properties are represented by the resulted compressive strength, splitting strength, bond strength, flexural strength, and permeability. Findings from this study revealed that density of LWGC specimens becomes lighter with increasing replacement percentage of GGBFS by SF and heavier with increasing MK content. The results showed that the mechanical properties for produced LWGC improved by replacing GGBFS partially with SF and reduced by using MK. The compressive strength for mix with 100% GGBFS was 17 MPa at 28 days. The maximum compressive strength and bond strength for all mixes obtained by mixing 90% GGBFS and 10% SF were 21.8 MPa at 28 days and 2.7 MPa, respectively. Increasing percentage of replacement of GGBFS with SF from 10% to 50% led to enhance in permeability, flexural strength and splitting strength by 57%, 7.5% and 12.35%. The partial replacement of GGBFS with MK with increased percentage up to 50% reduce the results of compressive strength, splitting strength, bond strength, flexural strength and permeability. | ||||
Keywords | ||||
geopolymer; pumice; expanded polystyrene; alkaline solution | ||||
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