Effect of Adding Graphite Nano/Micro Platelets on Salt Freeze-Thaw Resistance of Nano-Modificent Concrete

Abstract

Concrete is the most consumed material all over the world in construction industry. Though it is more stable than most of the materials, it has still some drawbacks that could be improved. Durability of concrete is main issue nowadays and different materials are added to concrete to improve it especially against frost actions. Nanotechnology has revolutionized the field of materials and present a great opportunity to improve the properties of concrete via successive nano-scaled modifications. Moreover, use of nano-waste particles contributes to add into effectiveness as ecofriendly concrete. Mitigation of nano-flaws will render concrete more robust to be used in environment where it is generally avoided. In this research, GNMP’s is induced into cementitious mix to make it more resilient in harsh conditions. Four different dosages of GNMP’s by mass of cement, 0.25%, 0.50%, 0.75%, 1.0% were induced in conventional concrete and its effect on salt frost resistance, acid attack, chloride migration, microstructure, porosity, volumetric stability, compressive strength in comparison to control sample were studied. Test result shows that concrete was still durable after 7,14,21 and 28 freeze-thaw cycles. Salt freeze-thaw response was evaluated from scaling and internal structure damage and freeze-thaw resistance was improved. Scanning electron micrographs have verified the crack branching and crack bridging effects of induced GNMP’s. GNMP’s may offer nucleation sites for hydration products (CSH gel) which make the microstructure dense and impermeable. Compressive strength before and after freeze-thaw exposure was determined and was enhanced with addition of GNMP’s. Scaling effect of acid attack was reduced with increase in GNMP’s content. Addition of GNMP’s has improved chloride permeability resistance of the matrix. Reduction in porosity and making the mix impermeable due to addition of GNMP’s was also verified from BET test results. 43% decrement was observed in shrinkage.