Performance of Workability and Compressive Strength on Self-Compacting Geopolymer Concrete Based On High-Calcium Fly Ash With Addictive Admixture

Abstract

Geopolymer concrete has been developed to replace conventional concrete with other pozzolan materials with a high silicate alumina content. Fly ash is a material that contains a high silicate alumina of 22%. The high content of Al and Si increases the compressive strength of concrete. High-calcium fly ash is abundantly found in Indonesia. However, it has not been widely used for industry or research, and this is due to the fast-hardening time of concrete. Therefore, it has the potential to be developed. High-quality concrete has a low cement water factor that causes low workability in concrete. Self-compacting geopolymer concrete (SCGC) has been developed as a high-quality, workable concrete innovation. Concrete is produced using gravel, sand, fly ash, alkaline activator, and water materials. This study used 14 Molar levels of NaOH. The variations used were 0%, 3%, 5%, and 7% superplasticizers (SP) made from polycarboxylate. This study used a dry mixing method to overcome the setting time on concrete. The results show that the workability achieved is 645mm, and the compressive strength achieved is 41.7 MPa.