Use of Rice Straw as Natural Fibers to Reinforce Concrete

Rice is one of the most important cereal crops in the world. Spain produces over 800.000 T/year of rice, and 14% is produced in the Valencian Community. Rice straw is an agricultural waste that is difficult to manage, and its introduction into concrete has been proposed to revalue this residue. This study shows preliminary experimental work carried out to prepare rice straw fibers and introduce them into a concrete mix. The resulting rice straw fibers had individual fiber lengths between 50 and 130 mm and diameters between 0.2 and 2 mm. Three concrete mixes have been studied: a reference mix and two concrete mixes with rice straw fibers in two dosages, 10 kg/m3 and 15 kg/m3. The properties analyzed are workability, compression flexural strength, and shrinkage. The results show that the rice straw fiber used in this work does not improve concrete properties or provide post-crack residual flexural strength. However, obtaining a concrete mix with enough strength for several engineering applications is feasible while incorporating this waste material.