Lightweight design and mechanical performance verification of surface structure of high-strength composite material houses based on computer topology optimization

The increasing demand for lightweight, high-performance building structures has driven the exploration of alternative construction materials and optimization-based structural design. This research examines the use of a lightweight material in high-strength concrete for surface structures of modern composite material houses. Expanded Clay Aggregate (ECA) partially replaces natural coarse aggregates to reduce structural weight while maintaining adequate mechanical performance. A systematic experimental program was conducted to evaluate both fresh properties (slump, compaction factor) and hardened concrete properties, includingcompressive strength (CS), flexural strength (FS), and split tensile strength (STS). The mixture design and optimization were performed using the response surface methodto identify the optimal proportion of ECA for achieving maximum strength and workability. Results indicate that up to 35% replacement of coarse aggregates with ECA produces concrete with CS ranging from 18-22 MPa, FS of 18-22% of CS, and STS of 9.5-11% of CS over 7-56 curing days. Mechanical performance verification through experimental testing and statistical analysis confirms that the ECA-based concrete meets structural requirements for surface applications. Statistical analysis through ANOVA demonstrates high model accuracy (R 2 > 0.99) and significance (p < 0.0001). In addition to experimental verification, computer-based structural modelling and topology-inspired design principles were applied to the surface structures, ensuring material efficiency, reduced weight, and enhanced load-bearing capacity. The combined approach of lightweight material incorporation and topology-informed designprovides a robust framework for developing structurally efficient, lightweight, and high-performance composite housing surfaces, providing both practical engineering applications and sustainable construction benefits.