Abstract:
Due to the rapid growth of infrastructure and the resulting increase in demand for construction
materials, cement usage has also increased. However, cement production is a significant
contributor to global carbon dioxide emissions, accounting for approximately 5% of the total. To
promote sustainability in the construction industry, it is essential for experts in engineering and
science to collaborate in developing and implementing eco-friendly building materials. The main
objective of this research to investigate the mechanical properties of geopolymer concrete
produced from locally available cementitious materials - ‘’Nech-Afer’’ and analysis failure mode
of concrete.
The study employed a geopolymer concrete mix design to determine the optimal superplasticizer,
molarity, and curing temperature based on mortar trials. Six samples of geopolymer concrete were
prepared, each with varying ratios of Na2SiO3 to NaOH of 2, 2.5, and 3 and replacement
percentages of soil of 25%, 50%, and 75%. For each variable, three sets of specimens were created
to test their compressive and split tensile strength at 7 and 28 days. A total of 120 specimens,
including concrete cubes and cylinders, were prepared and cured for 7 and 28 days. To investigate
the failure behavior of concrete under compressive load, a cubic specimen used for finite element
model is created as an experimental setup.
The results showed that using 14M and 2% of superplasticizer, along with a curing temperature of
80°C, resulted in a 17.27% increase over the control at a 75% replacement of Nech-afer in mortar
after 7 days. It appears that the slump value of the concrete increases with an increase in the
percentage of soil replacement, and also as the ratio of Na2SiO3 to NaOH increases, the
workability of the concrete increase. This study found that the compressive strength of the alkali activated concrete is better than the control mix for all ratios of Na2SiO3 to NaOH and up to 50%
of soil replacement at both the 7th and 28th-day ages. Additionally, the split tensile strength
improved for all ratios of Na2SiO3 to NaOH at 25% of soil replacement at 7th and 28th-day ages.
The combination of a 2.5 ratio of Na2SiO3 to NaOH and 50% of soil replacement resulted in the
highest split tensile strength. These results suggest that the alkali-activated concrete (AAC) with
14M, a 2.5 ratio of Na2SiO3 to NaOH, 2% of superplasticizer, 80°C curing temperature and 50%
of soil replacement is a suitable material for the construction industry. The investigation validated
the experimental and finite element results is differentiated 6.7% respectively.
