Title: Strengthening and retrofitting of low strength reinforced concrete slabs with high strength overlay: experimental and numerical investigation

Authors: Asad Ullah Qazi; Ali Murtaza Rasool; Muhammad Faheem Ud Din Afzal; Asif Hameed; Nadeem Mahmood; Noor Yaseen

Addresses: Civil Engineering Department, University of Engineering and Technology Lahore, Pakistan ' Diamer Basha Dam Consultants (DBCG) – National Engineering Services Pakistan (NESPAK), Lahore, Pakistan ' Department of Civil and Environmental Engineering, Florida International University, Miami, USA ' Civil Engineering Department, University of Engineering and Technology Lahore, Pakistan ' Civil Engineering Department, University of Engineering and Technology Lahore, Pakistan ' Civil Engineering Department, University of Engineering and Technology Lahore, Pakistan

Abstract: The study examined the effect of high-strength overlay on the flexural strength of low-strength reinforced concrete (RC) slabs weakened by inadequate curing conditions and aimed to validate these findings through numerical simulations. Although the concrete was specified to be 28 MPa, the slabs were cast with 18 MPa concrete. Eight 100 mm thick slabs were tested using the third-point loading test; two failed in the compression zone without any strengthening. The remaining six were reinforced with a 50 mm overlay of 35 MPa compressive strength: two with anchors, two with epoxy, and two with both anchors and epoxy. Additionally, two unstrengthened slabs were retrofitted, one with anchors and the other with epoxy. Results showed that strengthening and retrofitting increased the flexural capacity by 70% and shear capacity by 10%. The failure mechanism shifted from compression in unstrengthened slabs to shear in strengthened and retrofitted slabs. Numerical analysis corroborated the experimental results.

Keywords: experimental testing; numerical analysis; low strength rc slabs; high strength overlay.

DOI: 10.1504/IJSTRUCTE.2024.142108

International Journal of Structural Engineering, 2024 Vol.14 No.4, pp.416 - 436

Received: 24 Jan 2024
Accepted: 21 Jun 2024

Published online: 07 Oct 2024 *

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