LIU Xiaohui¹ ，PENG Xiaotong¹ ，WANG Hongwei² ，LI Weihai² ，WANG Peng¹

1. School of Civil Engineering and Architecture， University of Jinan， Jinan 250022， China；

2. China Railway Tenth Bureau Group Co. ， Ltd. ， Yantai 264001， China

Abstract

Objective With the rapid progress of urbanization， energy consumption in the construction industry has become increasingly concerning. Traditional autoclaved aerated concrete， though widely used， requires high energy during production， conflicting with low-carbon and energy-saving goals. Thus， developing non-autoclaved aerated concrete with low energy consumption and good thermal insulation is a key research direction. This study also seeks to enhance the use of solid waste， particularly waste glass powder. Waste glass， difficult to degrade， poses environmental risks if improperly handled. Incorporating waste glass powder in non-autoclaved aerated concrete not only mitigates environmental pollution but also improves its properties， such as lowering thermal conductivity and increasing compressive strength. This approach aligns with sustainability goals and promotes waste recycling. The research ultimately aims to prepare lightweight， high-strength， energy-efficient， and heat-insulating nonautoclaved aerated concrete，contributing to low-carbon， eco-friendly construction.

Methods In this study， orthogonal tests were conducted with two analysis approaches： range analysis and matrix correlation analysis. First， taking dry density and compressive strength as performance indicators， a L16（44） orthogonal experiment was designed examining four factors： cement content， aluminum powder content， polypropylene （PP） fiber content， and water-material ratio. Then， range analysis method was used to determine the influence of each factor on the performance of aerated concrete. Matrix analysis was applied to calculate the comprehensive weight of different levels of each influencing factor on multiple performance indicators to determine the optimal ratio for non-autoclaved aerated concrete. In addition， different amounts of glass powder （15%，20%，25%， and 30%） were used to replace fly ash， and their effects on performance indicators such as dry density， compressive strength， and thermal conductivity were investigated.

Results and Discussion Aluminum powder had the most significant impact on the dry density and compressive strength of nonautoclaved aerated concrete. With the increase in aluminum powder content， more bubbles formed in the concrete during the gas generation process， weakening the bonding strength between aggregates. As a result， it led to a gradual decrease in dry density and compressive strength. Cement content was identified as the second most influential factor： with the increase in cement content， the compressive strength increased initially but then decreased. This occurred because a certain increase in cement would promote aggregate reaction to generate more hydration products， thereby improving the compressive strength of aerated concrete.However， excessive cement content resulted in excessive hardening and shrinkage， negatively affecting compressive strength.The increase in water-material ratio and PP fiber content showed minimal impact on dry density， with a slight influence on compressive strength. The optimal mix ratio of the foundation was determined to be 24% cement content， a 0. 44 water-material ratio，0. 13% aluminum powder content， and 0. 4% PP fiber content. The introduction of glass powder as a substitute for fly ash reduced the thermal conductivity and improved the strength of aerated concrete. At a replacement rate of 25%， the basic properties of aerated concrete were optimal， with a dry density of 592 kg/m³， a compressive strength of 2. 6 MPa， and a thermal conductivity of 0. 071 94 W/（m·K）.

Conclusion This study shows that aluminum powder， cement， water-to-material ratio， and PP fiber have varying impacts on the dry density and compressive strength of non-autoclaved aerated concrete， with aluminum powder having the most notable effect. Incorporating glass powder as a fly ash substitute significantly enhances both thermal conductivity and compressive strength. The optimal material performance is achieved when the substitution rate of glass powder reaches 25%. While the thermal insulation of the prepared non-autoclaved aerated concrete exceeds current national standards， its compressive strength remains relatively low and requires further optimization. Overall， the study underscores the potential of non-autoclaved aerated concrete for energy efficiency， environmental sustainability， and material performance improvements. However， additional research is necessary to address the compressive strength limitations for practical engineering applications.

Keywords：non-autoclaved aerated concrete； glass powder； dry density； compressive strength； thermal conductivity； orthogonal test

DOI：10.13732/j.issn.1008-5548.2024.06.007