Performance of Porous Slabs Using Recycled Ash

Concrete technology has long focused on optimizing material properties for structural performance and environmental sustainability. Traditional concrete production is resource-intensive and contributes to high carbon emissions. In contrast, permeable concrete offers a dual benefit of water infiltration and reduced environmental impact. However, permeable concrete often lacks sufficient mechanical strength for widespread use. Prior research has shown that incorporating pozzolanic materials can enhance concrete properties. Yet, no prior work had resolved the specific effects of rice and wheat straw ash on permeable concrete performance. The need for locally sourced, eco-friendly alternatives to cement remains unmet. This gap motivated researchers to explore the use of agricultural byproducts in concrete formulations. The study addresses the challenge of balancing permeability with structural integrity. By integrating rice and wheat straw ash, the research aims to expand the application scope of permeable concrete.

The study aimed to assess the feasibility of replacing cement with rice and wheat straw ash in permeable concrete. The primary objective was to evaluate how these replacements affect mechanical and permeability properties. Researchers sought to determine optimal mix proportions for strength and porosity. The investigation also aimed to test the structural performance of reinforced slabs under flexural loads. A secondary goal was to validate experimental results using finite element modeling. The study focused on using locally available materials to reduce environmental impact. The researchers wanted to explore whether agricultural byproducts could replace cement without compromising performance. The ultimate aim was to identify viable applications for the resulting concrete in real-world settings.

The study involved two phases of concrete mix design and testing. In Phase I, nine concrete mixes were prepared using different proportions of rice and wheat straw ash. Mixes were grouped based on cement/aggregate ratios, sand content, and ash replacement levels. Fresh and hardened concrete tests were conducted to assess workability, permeability, and strength. In Phase II, six slabs were reinforced with different materials and tested under flexural loading. A finite element model was developed using ANSYS to simulate the experimental conditions. The model helped verify the accuracy of the physical tests. Researchers used standard testing procedures to measure compaction, porosity, and permeability. The study relied on controlled variables to isolate the effects of each material substitution.

Mixes containing rice and wheat straw ash showed increased compaction due to their spherical shape and larger surface area. Permeability and porosity slightly increased in these mixes compared to traditional pervious concrete. The interconnected voids likely contributed to this effect. Optimal porosity was achieved with 15% rice straw ash replacement. The reinforced slabs demonstrated structural performance under flexural loads. The finite element model confirmed the experimental results. The study found that rice straw ash at 15% replacement provided the best balance of properties. The results suggest that these materials can be viable alternatives to cement in permeable concrete.

The study demonstrated that rice and wheat straw ash can be used as partial replacements for cement in permeable concrete. The researchers propose that these materials improve compaction and porosity without compromising structural integrity. The findings suggest that rice straw ash at 15% replacement is optimal for performance. The use of agricultural byproducts reduces environmental impact and supports sustainable construction. The reinforced slabs performed well under flexural loads, indicating practical applications. The finite element model validated the experimental outcomes, supporting the reliability of the results. The study provides a foundation for using these materials in real-world applications such as parking lots and bridge walkways. The authors suggest that this approach could expand the use of permeable concrete in various construction contexts.