A study of the thermal properties of an alternative straw-containing building material

¹ TU Varna, Department of Thermal Engineering, 1,1 Studentska Str. 9010 Varna, Bulgaria
² VFU “Chernorizets Hrabar”, Department of Civil Engineering, Resort Chaika, 9007 Varna, Bulgaria

^* Corresponding author: pzlateva@tu-varna.bg

Abstract

Thermal comfort in buildings is usually achieved through sustainable materials obtained from natural sources, which justifies their use for developing building mixtures. Many natural materials were used as early as in ancient times to build homes that are warm in winter and cool in summer: a mixture of straw, clay and sand is an example of such a material. The objective of this article is to evaluate the effect of a mixture of clay, sand and straw on thermal comfort. For the purposes of this study, several types of sample plates were made from clay and sand mixture by adding different amounts of straw. The experiments were carried out and the thermal conductivity coefficient was determined using the method of infinite flat layer. The results indicate that the combination of different amounts of straw can be considered as good reinforcement of the sand and clay matrix and is characterized by a low thermal conductivity. Furthermore, 3D modelling was performed using Finite Element Analysis (FEA) software and a predictive model of the thermal behaviour of the samples from the different mixtures was developed. The thermal field distribution and the thermal conductivity coefficient thus determined were compared with the experimental data and showed consistency.