Investigations on thermal and mechanical properties of cement mortar with reed and straw fibers

Building insulation is commonly realized using materials obtained from petrochemicals or from natural sources processed with high energy consumptions, causing significant harmful effects on the environment. The “sustainability” applied to building design has encouraged many researches to develop thermal and acoustic insulating materials using natural or recycled materials. Many natural materials were already used in ancient times to thermally insulate the dwellings and to give resistance: straw and reed are some representative examples. Aim of this paper is to evaluate the influence of reed stems and straw on the thermal and mechanical performances of cement. To reach this, several types of mixes were prepared: a specimen as reference mix without any addition of fibers and some more specimens with reed only, with straw only, and finally the combination between straw and reed in different percentage. The tests were performed to determine the thermal conductivity, the compressive and flexural strength of the cement mortar panels. The results showed that straw, if combined with reed stems, could be considered as a valid reinforcement in a cementitious matrix characterized by enhanced thermal insulation and good mechanical properties. ENEA researchers have also applied a statistical method to the obtained test results in order to develop a predictive model of compression and flexural behavior of fiber-reinforced specimens with different percentages of organic fibers in the mixture cementitious.