DEVELOPMENT OF SELF-SENSING CEMENT-BASED COMPOSITE USING RICE-HUSK AND COAL BLEND BIOCHAR

Abstract

Pakistan being an agricultural country produces annually 7.2 million tons of rice which leads to the generation of an annual 2.3 million tons of rice-husk that goes to waste and is either burned away or dumped in the rivers. And biochar is a carbonaceous substance that has the potential to be used in developing multifunctional composites. Various researches have been conducted using different biomasses to produce biochars that alter the properties of cement composites in different ways such as improving its mechanical, physical, sensing, insulation, and many more properties. In this research study, three parts rice husk with one part coal was chosen as the biomass for biochar to develop a multifunctional cement composite that has a self-sensing ability. Contemporary methods of developing self-sensing composites involve the use of carbon fibers and carbon nano particles, which are quite expensive in Pakistan, rendering structural health monitoring an expensive option to adopt. Since biochar utilizes agro-waste, it is consequently cheaper and is an environmentally friendly alternative. The biochar was characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Laser Particle Size Analysis (LPSA) and Fourier Transform Infrared (FT-IR) spectroscopy. And it investigates the multifunctional attributes of the developed cement composites from the inclusion of the biochar in cement mortar which includes the effect on the compressive and flexural strength, electrical conductivity, carbon sequestration and the self-sensing ability of the composite. And as a result it was found that with the addition of 5% biochar compressive strength improved by 9.91%, with 10% biochar it improved by 36.44% and with 15% biochar it improved by 36.26%, however with increasing biochar, a reduction in ductility was observed. Flexural strength remained relatively same for all the formulations, while electrical conductivity increased by 9.7% for samples with 10% biochar addition. And the water absorption was also found for the same formulation to be 7.55%. Additionally, a strong linear correlation between fractional change in resistivity and strain was found with the coefficient of determination value for two of the data sets being R2 = 0.95702 and R2 = 0.96084 respectively. Proving this composite’s potential for usage in structural health monitoring applications as a multifunctional and ecofriendly material.