Worldwide, the purpose of enhancing sustainability, circular economy, use of by-products and renewable resources, has an increasing interest. Adding value to vegetable tropical resources is one of the challenges of COVACHIM-M2E laboratory. In this paper, sugar cane bagasse is evaluated both as mineral replacement and as reinforcement in cementitious matrices. In the modified matrix, cement is partly replaced by natural pozzolan and bagasse ashes, thus a ternary matrix is obtained. Composites materials are then elaborated by incorporation of bagasse fibers in this modified matrix (2 to 6 weight percent).The thermal conductivity and bending strength of the composites placed in a climatic chamber (25°C, 50% of relative humidity) are evaluated and compared to composites made with commercial cement and bagasse fibers, exposed to identical aging conditions.