Prediction of Stress-Strain Curves for HFRP Composite Confined Brick Aggregate Concrete under Axial Load

Panumas Saingam; Ali Ejaz; Nazam Ali; Adnan Nawaz; Qudeer Hussain; Panuwat Joyklad

doi:10.3390/polym15040844

Prediction of Stress-Strain Curves for HFRP Composite Confined Brick Aggregate Concrete under Axial Load

Polymers (Basel). 2023 Feb 8;15(4):844. doi: 10.3390/polym15040844.

Authors

Panumas Saingam¹, Ali Ejaz², Nazam Ali³, Adnan Nawaz⁴, Qudeer Hussain⁵, Panuwat Joyklad⁶

Affiliations

¹ Department of Civil Engineering, School of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
² National Institute of Transportation, National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan.
³ Department of Civil Engineering, COMSATS University Islamabad, Sahiwal Campus, Sahiwal 57000, Pakistan.
⁴ Department of Civil Engineering, COMSATS University Islamabad, Wah Campus, Wah 47040, Pakistan.
⁵ Center of Excellence in Earthquake Engineering and Vibration, Department of Civil Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
⁶ Department of Civil and Environmental Engineering, Faculty of Engineering, Srinakharinwirot University, Nakhonnayok 26120, Thailand.

Abstract

Recently, hemp-fiber-reinforced polymer (HFRP) composites have been developed to enhance the strength and ductility of normal and lightweight aggregate concrete along with recycled brick aggregate concrete. In addition, both experimental and analytical investigations have been performed to assess the suitability of the existing strength and strain models. However, the theoretical and analytical expressions to predict the stress-strain curves of HFRP-confined concrete were not developed. Therefore, the main objective of this study was to develop analytical expressions to predict the stress-strain curves of HFRP-confined waste brick aggregate concrete. For this purpose, a new experimental framework was conducted to examine the effectiveness of HFRP in improving the mechanical properties of concrete constructed with recycled brick aggregates. Depending on the strength of the concrete, two groups were formed, i.e., Type-1 concrete and Type-2 concrete. A total of sixteen samples were tested. The ultimate compressive strength and strain significantly increased due to HFRP confinement. Improvements of up to 272% and 457% in the ultimate compressive strength and strain were observed due to hemp confinement, respectively. To predict the ultimate compressive strength and strain of HFRP-confined concrete, this study investigated several existing analytical stress-strain models. Some of the strength models resulted in close agreement with experimental results, but none of the models could accurately predict the ultimate confined strain. Nonlinear regression analysis was conducted to propose expressions to predict the ultimate compressive strength and strain of HFRP-confined concrete. The proposed expressions resulted in good agreement with experimental results. An analytical procedure was proposed to predict the stress-strain curves of hemp-confined concrete constructed by partial replacement of natural coarse aggregates by recycled fired-clay brick aggregates. A close agreement was found between the experimental and analytically predicted stress-strain curves.

Keywords: fired-clay brick aggregates: recycled aggregate concrete; hemp fiber rope; stress–strain models.

Grants and funding

[KREF206601.Academic Melting Pot]./King Mongkut's Institute of Technology Ladkrabang