Abstract
For ages, concrete has been used to construct underwater structures. Concrete laying underwater is a very complex procedure important to the success or failure of underwater projects. This paper elucidates the influence of alkali activator ratios on geopolymers for underwater concreting; focusing on the geopolymer concrete synthesized from fly ash and kaolin activated using sodium hydroxide and sodium silicate solutions. The geopolymer mixtures were designed to incorporate multiple alkali activator ratios to evaluate their effects on the resulting geopolymers’ properties. The fresh concrete was molded into 50 mm cubes in seawater using the tremie method and tested for its engineering properties at 7 and 28 days (curing). The control geopolymer and underwater geopolymers’ mechanical properties, such as compressive strength, water absorption density, and setting time were also determined. The differences between the control geopolymer and underwater geopolymer were determined using phase analysis and functional group analysis. The results show that the geopolymer samples were optimally strengthened at a 2.5 alkali activator ratio, and the mechanical properties of the control geopolymer exceeded that of the underwater geopolymer. However, the underwater geopolymer was determined to be suitable for use as underwater concreting material as it retains 70% strength of the control geopolymer.
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Authors and Affiliations
Fakhryna Hannanee Ahmad Zaidi
1
ORCID:
Romisuhani Ahmad
1
2
ORCID:
Mohd Mustafa Al Bakri Abdullah
3
2
ORCID:
Wan Mastura Wan Ibrahim
1
2
ORCID:
Ikmal Hakem Aziz
3
2
ORCID:
Subaer Junaidi
4
ORCID:
Salmabanu Luhar
5
2
ORCID:
- Universiti Malaysia Perlis, Faculty of Engineering Technology, Sungai Chuchuh, 02100 Padang Besar, Perlis, Malaysia
- Universiti Malaysia Perlis (UniMAP), Geopolymer & Green Technology, Centre of Excellence (CEGeoGTech), Perlis, Malaysia
- Universiti Malaysia Perlis, Faculty of Chemical Engineering Technology, Taman Muhibbah, 02600 Jejawi, Arau, Perlis, Malaysia
- Universitas Negeri Makassar, Geopolymer & Green Material Group, Physics Department, FMIPA, Indonesia
- Frederick Research Center, P.O Box 24729, 1303 Nicosia, Cyprus