DEVELOPMENT OF METAKAOLIN SELF-COMPACTING CONCRETE FOR PAVEMENT

Busari, A. A. and Covenant University, Theses (2018) DEVELOPMENT OF METAKAOLIN SELF-COMPACTING CONCRETE FOR PAVEMENT. ["eprint_fieldopt_thesis_type_engd" not defined] thesis, COVENANT UNIVERSITY.

PDF Download (419kB)

Abstract

Defects of asphaltic concrete pavements in Nigeria due to the effect of high axle vehicle have become a stigma. Hence, the recent interest in rigid pavements as a sustainable solution. The high strength required for rigid pavements is often achieved by the use of additives and admixtures to concrete during production. In this study, the choice of metakaolin in selfcompacting concrete for rigid pavement construction was assessed. This research was divided into three stages. The first stage involved the development of Metakaolin Self-Compacting Concrete (MKSCC) and Pigmented Metakaolin Self-Compacting Concrete (PMKSCC) using two brands of cement. The rheology and strength properties of twenty-four (24) concrete mixes were examined at 3, 7, 14, 21, 28, 56, 91, 121 and 150 days. Pavement application of the strength parameters was assessed using AASHTO specifications. The second stage involved the Mechanistic-Empirical design of a typical high axle road and the assessment of the stressstrain parameters using Finite Element Analysis. Numerical analysis of the strength parameters was done in the third stage using Response Surface Analysis. The result of the rheology showed that 10% addition of metakaolin showed satisfactory results. However, at higher percentages, the passing ability, flowing ability, and the segregating ability became unsatisfactory. The pavement application of the strength properties recorded showed that at 10% replacement, the flexural strength of 4.86 MPa was obtained. This strength value is higher than the required specification of 4.27 MPa for pavement construction at 28 days; it also satisfies the requirement for high axle and airfield pavement. In a bid to minimize cost, the use of MKSCC (B) in concrete pavement is appropriate, as the strength properties were satisfactory up to 20%. However, to optimize strength, the use of MKSCC (A) is appropriate as it showed the highest strength The Mechanistic-Empirical pavement design of a typical high axle section of Abaji road (Northern Nigeria) gave a thickness of 254 mm and 251.5 mm for the two MKSCC developed. This was used in establishing the stress-strain relationship using Finite Element Analysis. The result revealed that 6.5 % stress was reduced based on the modulus of elasticity of the MKSCC and the control. The displacement in the pavement was noticed at the symmetry line where the tandem wheel load was applied. Numerical analysis using response surface model revealed that at a low value of Metakaolin, a positive relationship exists between the strength parameters and age of concrete. From the numerical optimization obtained, the maximum predicted compressive and flexural strength of 44.35 N/mm2 and 6.18 MPa is achievable under the optimum concrete formation of 110 days, a metakaolin content of 52.73 Kg and water/cement ratio of 0.4. The desirability of 1.00 was achieved with the numerical optimization performed, showing the best accuracy of the optimization process. Additionally,the R2 value of 0.91 % was obtained from the model equation which established the robustness of the model. Ultimately, this research revealed that the choice of metakaolin in selfcompacting concrete for rigid pavement construction reduced the construction cost and increased the strength of the pavement. Hence MKSCC is a strong, sustainable, and ecofriendly alternative in rigid pavement construction.

Item Type:	Thesis (["eprint_fieldopt_thesis_type_engd" not defined])
Uncontrolled Keywords:	Pavement, Sustainability, Metakaolin, Self-compacting Concrete, Pigments, Finite Element Analysis
Subjects:	T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General)
Divisions:	Faculty of Engineering, Science and Mathematics > School of Civil Engineering and the Environment
Depositing User:	Mrs Hannah Akinwumi
Date Deposited:	02 Nov 2020 11:25
Last Modified:	02 Nov 2020 11:25
URI:	http://eprints.covenantuniversity.edu.ng/id/eprint/13696

Actions (login required)

View Item