Fly ash is a byproduct of coal combustion that has been used as a supplementary cementitious material in concrete for many years. It is known to improve the work-ability, durability, and strength of concrete. However, its low hydration at an early stage can cause the strength of fly ash brick to be low. In this study, we aimed to find the optimum mix percentage of fly ash brick with the addition of lime, gypsum, and quarry dust to improve its compressive strength.
The experiment involved casting brick specimens of size 230mm x 110mm x 90mm for different mix percentages of fly ash (15% to 50%), gypsum (2%), lime (5% to 30%), and quarry dust (45% to 55%). Compressive strength was studied for different mix proportions at different curing ages. The results showed the variation of compressive strength for different mix proportions of materials mentioned earlier at different curing ages.
From the results, it was inferred that the maximum optimized compressive strength is obtained for optimal mix percentage of Flyash – 15%, Lime- 30%, Gypsum – 2%, Quarry dust – 53%. The key words in this study were Fly ash, Lime, Gypsum, Quarry dust, Compressive strength and Water absorption.
The use of fly ash in construction has many advantages such as reducing greenhouse gas emissions and conserving natural resources. However, its low early-stage hydration can cause problems with the strength development of concrete or bricks made from it. This study aimed to find a solution to this problem by optimizing the mix percentage of fly ash brick with the addition of lime, gypsum, and quarry dust.
The Taguchi method was used in this study to experimentally investigate the fly ash brick mix proportions. The least quantity of cement and fly ash was used as binding materials while considering water binder ratio as a control factor. The effects of water/binder ratio, fly ash, coarse sand, and stone dust on the performance characteristics were analyzed using signal-to-noise ratios and mean response data.
The results of this study showed that the compressive strength of fly ash brick can be improved by optimizing the mix percentage of fly ash, lime, gypsum, and quarry dust. The maximum optimized compressive strength was obtained for an optimal mix percentage of Flyash – 15%, Lime- 30%, Gypsum – 2%, Quarry dust – 53%. This result is significant because it shows that fly ash brick can be made stronger by adding small amounts of other materials.
The addition of lime and gypsum to fly ash brick was found to have a positive effect on its compressive strength. Lime is known to improve the workability and durability of concrete, while gypsum acts as a retarder, slowing down the setting time of the mixture. The addition of quarry dust also had a positive effect on the compressive strength of fly ash brick. Quarry dust is a waste material that is generated during the crushing process of stones and can be used as a replacement for sand in concrete or bricks.
The results of this study are significant because they provide a solution to the problem of low early-stage hydration in fly ash brick. By optimizing the mix percentage of fly ash, lime, gypsum, and quarry dust, it is possible to improve the compressive strength of fly ash brick without increasing its cost significantly.
In addition to improving the compressive strength of fly ash brick, this study also analyzed its water absorption characteristics. Water absorption is an important property for building materials because it affects their durability and resistance to weathering. The results showed that the water absorption rate decreased with an increase in fly ash content and an increase in curing time.
Overall, this study provides valuable insights into how fly ash brick can be made stronger by optimizing its mix percentage with other materials such as lime, gypsum, and quarry dust. The results show that it is possible to improve the compressive strength of fly ash brick without significantly increasing its cost or negatively impacting its other properties such as water absorption.
This study highlights the importance of optimizing mix proportions for building materials such as fly ash brick. By doing so, it is possible to improve their performance characteristics such as compressive strength and water absorption without significantly increasing their cost or negatively impacting other properties. This research provides valuable insights into how we can make our buildings more durable and sustainable by using innovative solutions like optimized mix proportions for building materials.