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Investigation of the properties of green concrete exposed to different aggressive environments

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Akram O. Kadhum at University of Babylon
Akram O. Kadhum
Abbas AL-Ameeri at University of Brighton
Abbas AL-Ameeri
Shaker J. Edrees
Shaker J. Edrees
Shaker J. Edrees
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The durability of reinforced concrete structures constructed in Iraq is affected by different environmental factors, where the two most common and harmful factors on the durability of concrete are the presence of chloride and sulfate salts in the surrounding environment. Therefore, the main objective of the research is to study the combined effect of these salts on the properties of green concrete, knowing that the individual impact of these salts has been widely studied. Still, there is a lack of understanding regarding how they interact and how their combined presence affects the durability and service life of concrete. In addition, its durability can be improved by replacing cement with supplementary cementitious materials thus reducing carbon dioxide emissions. To achieve this goal, seven mixtures were prepared, one of which was a reference without any substitute and six mixtures that included silica fume (SF) and ground granulated blast furnace slag (GGBS) independently and in varying amounts (3, 5, 7% SF) and (30, 40, 50% GGBS). After adequate curing, they were exposed to aggressive chemicals: (5% sodium chloride + 2% calcium chloride), (5% sodium sulfate), and combined (5% sodium chloride + 2% calcium chloride + 5% sodium sulfate), in addition to tap water (i.e. reference). Strength and durability were evaluated using tests including compressive strength, electrical resistivity, porosity, total absorption and length change, along with repeated visual inspections. In addition, the intensity of chlorine and sulfur components in the concrete was evaluated using X-ray diffraction. The results indicated less deterioration in concrete samples with silica fume and GGBS compared to the reference mixture (without replacing) exposed to the above solutions. Chloride ions do not cause deteriorated effects on concrete and enhance its physical and mechanical properties, which is essential for their role in mitigating sulfate attacks on concrete. In the combined solutions, the deterioration is less severe than in the sulfate solutions. The inhibitory mechanism of chloride ions on concrete sulfate attack indicates that while they cannot completely prevent sulfate attack, they can somewhat mitigate the associated risk. Mixtures with the highest replacement ratio (7% SF and 50% GGBS) showed the highest resistance to aggressive environments and the highest durability.
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Vol.:(0123456789)
Journal of Building Pathology and Rehabilitation (2025) 10:93
https://doi.org/10.1007/s41024-025-00601-z
RESEARCH ARTICLE
Investigation oftheproperties ofgreen concrete exposed todifferent
aggressive environments
AkramO.Kadhum1· AbbasS.AL‑Ameeri1· ShakerJ.Edrees2
Received: 23 November 2024 / Revised: 16 February 2025 / Accepted: 6 March 2025
© The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025
Abstract
The durability of reinforced concrete structures constructed in Iraq is affected by different environmental factors, where
the two most common and harmful factors on the durability of concrete are the presence of chloride and sulfate salts in the
surrounding environment. Therefore, the main objective of the research is to study the combined effect of these salts on the
properties of green concrete, knowing that the individual impact of these salts has been widely studied. Still, there is a lack of
understanding regarding how they interact and how their combined presence affects the durability and service life of concrete.
In addition, its durability can be improved by replacing cement with supplementary cementitious materials thus reducing
carbon dioxide emissions. To achieve this goal, seven mixtures were prepared, one of which was a reference without any
substitute and six mixtures that included silica fume (SF) and ground granulated blast furnace slag (GGBS) independently
and in varying amounts (3, 5, 7% SF) and (30, 40, 50% GGBS). After adequate curing, they were exposed to aggressive
chemicals: (5% sodium chloride + 2% calcium chloride), (5% sodium sulfate), and combined (5% sodium chloride + 2%
calcium chloride + 5% sodium sulfate), in addition to tap water (i.e. reference). Strength and durability were evaluated using
tests including compressive strength, electrical resistivity, porosity, total absorption and length change, along with repeated
visual inspections. In addition, the intensity of chlorine and sulfur components in the concrete was evaluated using X-ray
diffraction. The results indicated less deterioration in concrete samples with silica fume and GGBS compared to the reference
mixture (without replacing) exposed to the above solutions. Chloride ions do not cause deteriorated effects on concrete and
enhance its physical and mechanical properties, which is essential for their role in mitigating sulfate attacks on concrete. In
the combined solutions, the deterioration is less severe than in the sulfate solutions. The inhibitory mechanism of chloride
ions on concrete sulfate attack indicates that while they cannot completely prevent sulfate attack, they can somewhat mitigate
the associated risk. Mixtures with the highest replacement ratio (7% SF and 50% GGBS) showed the highest resistance to
aggressive environments and the highest durability.
Keywords Green concrete· GGBS· Silica fume· Chloride attack· Sulfate attack· Combined attack
1 Introduction
Concrete is among the most often utilised construction
materials globally. Nonetheless, the production of ordinary
Portland cement (OPC), an essential component of concrete,
generates significant volumes of carbon dioxide (CO2) and
other greenhouse gases (GHGs); one tonne of OPC produces
approximately one tonne of CO2 and additional GHGs [1].
Environmental concerns associated with greenhouse gases,
together with the loss of natural resources, have significantly
influenced the long-term advancements of the cement and
concrete industry throughout this century [2]. Aside from
water, concrete is the only substance consumed in such vast
quantities by humans [3]. Recent trends in urbanisation and
* Akram O. Kadhum
akram.kadhum.engh363@student.uobabylon.edu.iq
Abbas S. AL-Ameeri
abbas.alameeri.eng@uobabylon.edu.iq
Shaker J. Edrees
mat.shaker.jahil@uobabylon.edu.iq
1 Department ofCivil Engineering, College ofEngineering,
University ofBabylon, Karbala, Iraq
2 Department ofCeramic andBuilding Materials, College
ofMaterials Engineering, University ofBabylon, Karbala,
Iraq
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