Lightweight Concrete as an Alternative to AAC Blocks for Slab Levelling

Abstract

Lightweight concrete, particularly foam concrete, has emerged as a potential material in modern construction due to its low density, improved thermal and sound insulation, and ease of use. This material is created by mixing a stable foam with a cement-based composition, resulting in air bubbles inside the matrix. The entrained air gaps dramatically reduce the density of the concrete, making it lighter and more adaptable than conventional choices. The aim of this project is to investigate the properties, applications, and practical implications of foam concrete, especially in high-rise buildings and prefabricated structures, where load reduction on foundations is crucial. Key aspects of this research include examining the compressive strength, thermal conductivity, workability, and durability of foam concrete across different densities. Various mix designs will be tested to determine the optimal balance between lightweight benefits and structural performance, ensuring that the material remains suitable for both load-bearing and non-load-bearing applications. The study will also explore the environmental advantages of foam concrete, given its reduced need for raw materials and potential use of recycled components, making it a sustainable alternative in the context of eco-friendly construction practices. By the end of this research, findings are expected to provide actionable insights into the use of foam concrete in diverse construction scenarios, highlighting its potential as a sustainable, efficient, and practical solution for future project

Introduction

Lightweight concrete, especially foam concrete, is increasingly popular in construction due to its low density, thermal insulation, soundproofing, and ease of use. Unlike traditional heavy concrete, foam concrete incorporates stable air bubbles in the mix, reducing weight and structural dead load—beneficial for applications like high-rise buildings and roof slabs. Its fluidity allows filling complex shapes and voids efficiently. Foam concrete is also eco-friendly, using recyclable materials such as fly ash, and improves energy efficiency due to its insulation properties.

Autoclaved Aerated Concrete (AAC) is a type of lightweight precast foam concrete made from aluminum powder, cement, lime, gypsum, and fly ash, cured under steam pressure. AAC blocks are widely used for insulation and non-structural applications.

This study aims to evaluate lightweight concrete as a cost-effective, efficient alternative to AAC blocks for slab levelling, focusing on structural performance, cost, and time efficiency. The context involves addressing a 275 mm slab height discrepancy in a construction project where traditional concrete is unsuitable due to slab load limits.

The methodology includes developing lightweight concrete mixes with suitable aggregates or foaming agents, testing workability and strength, and comparing results with AAC blocks. A detailed cost and time analysis will assess material costs, labor, equipment, and project scheduling. Field and lab tests will validate performance criteria such as bonding, curing, and durability.

The project’s goal is to recommend an optimized, practical levelling solution that meets structural, economic, and construction timeline requirements, offering guidelines for future similar applications.

Conclusion

Based on the findings of this study, it can be concluded that lightweight concrete presents a technically viable and practically efficient alternative to Autoclaved Aerated Concrete (AAC) blocks for slab leveling applications in modern construction. The experimental and analytical evaluations demonstrated that lightweight concrete achieves structural performance comparable to AAC blocks, making it suitable for non-load bearing applications such as floor leveling, where strength and stability are essential but not critical in a load-bearing context. One of the major advantages observed is its superior workability, which allows for easier mixing, placing, and leveling on site. This property significantly reduces construction time and contributes to faster project execution, especially in multi-unit residential and commercial buildings. Unlike AAC blocks, which require precise cutting, alignment, and bonding, lightweight concrete can be poured or pumped directly over the surface, minimizing labor dependency and reducing human error during application. In terms of cost-efficiency, lightweight concrete offers savings in both material handling and labor costs. Since it is pumpable and self-leveling in nature, it eliminates the need for additional finishing layers or extensive manual adjustments, which are often required with AAC block leveling. Furthermore, its lower density reduces the dead load on slabs, which may allow for optimization in structural design and further material savings in the long run. The material also displayed a lower tendency to develop surface cracks, enhancing the durability and finish quality of the slab. Its adaptability to different slab configurations and on-site conditions—including uneven or irregular surfaces—adds to its versatility and makes it particularly suitable for both new construction and renovation projects. Overall, lightweight concrete proves to be a more adaptable, time-efficient, and cost-effective solution compared to AAC blocks for slab leveling. Its practical advantages, combined with acceptable structural behavior, position it as a strong candidate for widespread use in modern construction practices.

References

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Copyright

Copyright © 2025 Mr. Rushikesh Avinash Borate , Prof. Ankita Turate. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.