2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
The Effects of Superabsorbent Polymer (SAP) on Concrete in Marine Environment


Author(s)
Dr. Opeyemi Joshua, Department of Building Technology, Covenant University. Nigeria (Presenter)
Dr. Olatokunbo Ofuyatan, Covenant University
Dr. Ayobami Busari, Covenant University
Dr. Isaac Akinwumi, Department of Civil Engineering, Covenant University, Ota, Nigeria
Mr. David O. Nduka, Department of Building Technology, Covenant University, Nigeria.
Mr. Ayodele O. Ibitayo, Department of Building Technology, Covenant University, Nigeria.
Dr. Olayinka Oloke, Department of Estate Management, College of Science and Technology, Covenant University,
Abstract

The quest for high strength concrete (HSC) has given rise to the use of several blends/additives with cement like silica fumes, fly ash and granulated blast furnace slag. The major technique employed to achieve HSC is lower water/cement (w/c) ratio. One major additive used to achieve very low w/c ratio is the superabsorbent polymer (SAP) with superplasticizers. SAP which is applicable in HSC can hold water in concrete and gradually release it for curing for optimal strength development where external curing water cannot easily access. The very high water absorbent property of SAP is the desired characteristics in HSC applications, but when it is exposed to sodium chloride (NaCl) salt, it rapidly losses its absorbent property and hence, the ability to improve strength in concrete. The major solute in marine water is NaCl at varying concentrations. This study aims to assess the effects of the NaCl in the marine environment on the SAP within the concrete and its effect on the concrete strength. Normal-strength class concrete was used in this study and cured in marine water, this is to allow for better curing-water (with dissolved NaCl) ingress into the concrete to magnify the effect. Concrete mix-design to attain a target strength of 30MPa was mixed and cast into 100mm cube mold. The control was cast and cured in fresh and marine water, the test concrete cubes were mixed with SAP and cured in marine and fresh water. Superplasticizers were used in all the mixes. Result shows that concrete cast with SAP required more water for good workability but the ones cured in the marine water had significant reduced strength than the ones cured in fresh water. More significant strength difference was observed with the SAP concrete cubes cured in fresh and marine waters. This study concludes that there is a significant interaction between the SAP and the marine water. It is recommended that microstructural studies be performed to study the salt-SAP interaction that resulted in reduced strength.