Thermal Behavior Analysis of Natural Composites Materials Comprising Diatomaceous Earth and Sugarcane Bagasse

This work quantifies the thermal performance of natural composite blocks made from Yapatera diatomaceous earth reinforced with sugarcane bagasse fibres. Prismatic specimens (185 × 185 mm) with three thicknesses (≈76 mm, 100 mm, and 150 mm) and bagasse contents of 5–15% (wt.) were tested at hot-face temperatures of 100, 250, and 450 °C in a full-factorial 3 × 3 × 3 plan (54 tests). Thermal conductivity (k) was measured using a guarded hot-plate device aligned with ASTM D5470/E1530/C177. The measured k averaged 0.125 W/m·K (range ~0.088–0.220 W/m·K) and remained stable in function up to 500 °C. ANOVA showed that temperature and thickness significantly increased k (p < 0.05), while fibre content had a weaker, non-monotonic effect beyond ~10%. A response-surface model (RSM) provided accurate predictions (R2 ≈ 0.95). For design purposes, thermal resistance was computed as . A 150 mm block yielded R ≈ 1.20 m2K/W, comparable to ~0.40 m of hollow ceramic brick and > 1.0 m of concrete to reach a similar R. The composite therefore occupies a distinct niche: medium-performance insulation with high-temperature stability (≤ 500 °C), low embodied energy (air-dried manufacturing, agro-waste feedstock), and competitive cost potential. These results support its use in industrial and building applications where conventional insulators are unsustainable or operate below the required temperature window.