The Effect of Rice Husk on the Variability of Physical and Mechanical Properties of Composites

What is it about?

Rice husk (RH) is one of the most commonly grown and consumed cereals in the world. Due to its low nutritional value, it is not commonly used as a food or fertilizer. Instead, it is often burned or landfilled. To develop rice husk-based composites for thermal and acoustic non-structural applications, a balance between achieving satisfactory performance in physical and mechanical properties is essential, as well as ensuring reliability and predictability in the behavior of the composites. The inclusion of RH in composites can result in increased variability in their performance. The RH used in the study was collected from Baixo Mondego, Portugal, and approximately 90% of the particles had sizes ranging from 1 mm to 4 mm. To reduce cement usage, different mixtures were produced and categorized based on the use of two types of cement, varying percentages of limestone filler and different quantities of RH. A study was conducted to assess whether a specific mixture formula within a given group exhibited consistent behavior across different batches or yield intrinsically different results. This helps to identify the key adaptations required in the industrial process of incorporating this biomaterial into composites. The results have shown that it is possible to produce rice husk-based composites with less variability of performance and potential for non-structural applications. In this case, cement CEM II/A-L 42.5 R type with limestone filler addition was the most sustainable mix design, since it had a small variability of results and reduced the cement content.

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