Mechanical Properties of Lightweight Concrete Incorporating Perlite, LECA, and Supplementary Materials

Abstract

Lightweight structural materials are increasingly essential in modern construction, particularly in seismic-prone regions, as they reduce self-weight while maintaining mechanical reliability and improving earthquake resilience. This study investigates the mechanical behavior of lightweight concrete mixtures produced using expanded perlite and Light Expanded Clay Aggregate (LECA), combined with stone powder and microsilica to enhance matrix densification, with Ordinary Portland Cement (Type I) and potable tap water used across all mixes. Four lightweight mixtures—C350L40P15, C300L60P5, C400L40P15, and C400L50P10—were designed and compared with a reference concrete. Results showed substantial reductions in compressive strength (35.4%–54.2%), with C400L40P15 achieving the highest value of 26 MPa. Indirect tensile strength decreased by 16.3%–32.5%, yet mixtures with higher perlite content demonstrated notable improvements, achieving up to 19.4% greater strength compared with lower-perlite. Flexural tensile strength declined by 28.6%–41.3% relative to the reference, with C400L40P15 again showing the best performance (4.5 MPa). The elastic modulus exhibited the largest reductions (54.3%–65.7%) due to lower density, though it increased with higher cement content and reduced water-to-cement ratio. Overall, the findings indicate that optimized perlite content, controlled density, and the incorporation of stone powder collectively enhance the tensile, flexural, and stiffness properties of lightweight concrete, highlighting its potential for structural applications in earthquake-prone areas where reduced density is crucial for improving seismic performance without severely compromising mechanical strength.