COMPARATIVE ASSESSEMENT OF THE DEFLECTION OF PRESTRESSED GEOPOLYMER CONCRETE AND PRESTRESSED ORDINARY PORTLAND CONCRETE

ABSTRACT

This project focuses on a comparative assessment of the deflection behavior of prestressed ordinary Portland cement (OPC) and prestressed geopolymer concrete (GPC) beams. The primary aim is to evaluate the deflection performance of geopolymer concrete beams in comparison to OPC beams. To achieve this, various tests are conducted on the materials used, including sieve analysis of aggregates, setting time tests for cement and metakaolin, workability assessments, and specific gravity tests on aggregates. Additionally, supporting tests such as compressive strength tests of OPC and GPC are performed. The core of the study involves flexural testing of prestressed beams made from both OPC and GPC. The tests on the materials to be used will be the sieve analysis test on aggregates, the setting time test on cement and metakaolin, the workability of concrete and metakaolin, and the specific gravity test on aggregates. The other supporting tests to be carried out are the compressive strength test of ordinary Portland cement and geopolymer concrete. Finally, the assessment of the prestressed beams will be carried out. Preliminary findings indicate that metakaolin, which has been successfully calcined, demonstrates reactivity when exposed to alkaline activators. The resulting metakaolin-based geopolymer concrete exhibits rapid strength development, surpassing OPC concrete in the short term. The compressive strengths of the geopolymer concrete (GPC) measured were 43N/mm² at 24 hours, 47N/mm² at 3 days, and 49N/mm² at 7 days which were higher than the compressive strengths of ordinary Portland cement (OPC). From the results, the geopolymer concrete beams prepared from 8 molarity of NaOH have higher moment capacity (an average of 482.36 Nm) of those prepared by 10 and 12 molarity (with the range of 338.0 – 349.5 Nm). Also, the 8-molarity concrete has higher compressive strength than that of the 10 and 12 molarity. This project aims to analyze and compare the deflection characteristics of the two types of prestressed beams, supported by comprehensive material and strength tests.