Experimental and finite element analysis for the flexural behavior of notched geopolymer beam under Monotonic load

Abstract

Concrete is frequently used to build infrastructure, its main component, cement, has a substantial negative influence on the environment. The production of cement degrades the environment by using a lot of energy and emitting a lot of CO2 s. Alternative cementitious materials, on the other hand, are usable and have less of an adverse effect on the environment. These materials, which have high silicon and aluminum content, can aid in lowering energy use as well as CO2 emissions. Accessible locally natural Cementous materials to improve the sustainability of construction endeavors. Using a four-point flexural test to assess the post-performance of a beam following a pre-crack. The aim of this study is to investigate the flexural behavior of notched geopolymer beams under monotonic load. The study investigated the use of white soil (Nech Afer), a locally available cementitious material, as a volume 50% replacement for cement. It was investigated how different alkaline solution concentration and maximum aggregate sizes affected the compressive strength and flexural performance of geopolymer concrete beam. In general, this study offers insightful information about the prospective application of substitute materials in geopolymer concrete of C-20/25 grade and their effect on the structural performance. Three phases of experimental study were conducted. The first mortar study involved altering the proportions of molarity of Alkaline solution 12, 14, and 16, white soil replacements 25%, 50%, and 75%, and superplasticizer 1.5% and 2%. 18 different mortar mixtures, total 54 samples 50 mm x 50 mm x 50 mm geopolymer mortar cubes were produced. In the second stage of the investigation, 150 mm x 150 mm x 150 mm geopolymer concrete cubes made from six different geopolymer concrete mixes, total 36 samples were utilized to evaluate the mechanical properties of concrete. The third phase post-performance under four-point flexural notch beam 100 mm x 100 mm x 500 mm with notched dimensions of 2 mm width and 25 mm deep were made. Total 27 samples of these beams, with nine different mix design were used. The other independent variable changes the maximum aggregate size to 10 mm, 12.5 mm, and 16 mm. All samples were using volume method mix design and cured for 24 hours at 85 °C oven dry and then placed in ambient temperature for a maximum of 28 days. Test result directs 12 Molarity 1.5% superplasticizer and 14 Molarity 2% superplasticizer with 50% white soil (Nech Afer) record 26MPa was optimum in first phase. As the molarity of Alkaline solution increase from 12 molarity to 14 molarity both compressive and notch beam strength of geopolymer concrete was increase 6.3% and 32.84%. As maximum coarse aggregate size increase both compressive and notch beam strength decrease by 6.5% and 25.5%. Modules of rupture increase for normal concrete notch beam as maximum coarse aggregate size increase. Finite element analysis validates with accuracy of 94.9%.