Multi-Objective Optimization of Sustainable Concrete Containing Fly Ash Based on Environmental and Mechanical Considerations
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Buildings
Abstract
Infrastructure design, construction and development experts are making frantic efforts
to overcome the overbearing effects of greenhouse gas emissions resulting from the continued
dependence on the utilization of conventional cement as a construction material on our planet.
The amount of CO2 emitted during cement production, transportation to construction sites, and
handling during construction activities to produce concrete is alarming. The present research work
is focused on proposing intelligent models for fly ash (FA)-based concrete comprising cement, fine
and coarse aggregates (FAg and CAg), FA, and water as mix constituents based on environmental
impact (P) considerations in an attempt to foster healthier and greener concrete production and aid
the environment. FA as a construction material is discharged as a waste material from power plants
in large amounts across the world. Its utilization as a supplementary cement ensures a sustainable
waste management mechanism and is beneficial for the environment too; hence, this research work is
a multi-objective exercise. Intelligent models are proposed for multiple concrete mixes utilizing FA as
a replacement for cement to predict 28-day concrete compressive strength and life cycle assessment
(LCA) for cement with FA. The data collected show that the concrete mixes with a higher amount of
FA had a lesser impact on the environment, while the environmental impact was higher for those
mixes with a higher amount of cement. The models which utilized the learning abilities of ANN
(-BP, -GRG, and -GA), GP and EPR showed great speed and robustness with R2 performance indices
(SSE) of 0.986 (5.1), 0.983 (5.8), 0.974 (7.0), 0.78 (19.1), and 0.957 (10.1) for Fc, respectively, and 0.994
(2.2), 0.999 (0.8), 0.999 (1.0), 0.999 (0.8), and 1.00 (0.4) for P, respectively. Overall, this shows that
ANN-BP outclassed the rest in performance in predicting Fc, while EPR outclassed the others in
predicting P. Relative importance analyses conducted on the constituent materials showed that FA
had relatively good importance in the concrete mixes. However, closed-form model equations are
proposed to optimize the amount of FA and cement that will provide the needed strength levels
without jeopardizing the health of the environment.
Description
Keywords
Green concrete, Fly ash (FA), Sustainable construction materials, Life cycle assessment (LCA), Environmental impact (EI), Artificial intelligence (AI)
Citation
Onyelowe, K.C.; Kontoni, D.-P.N.; Ebid, A.M.; Dabbaghi, F.; Soleymani, A.; Jahangir, H.; Nehdi, M.L. Multi-Objective Optimization of Sustainable Concrete Containing Fly Ash Based on Environmental and Mechanical Considerations. Buildings 2022, 12, 948. https://doi.org/ 10.3390/buildings12070948