Experimental analysis of the impact of alternating magnetic fields on the compressive strength of concrete with various silica sand and microsilica compositions

This research experimentally assessed the compressive strength enhancement of 7- and 28-day concrete specimens with up to 20 % silica sand and micro silica under an alternating magnetic field up to 1 Tesla. By applying magnetic fields to hardened concrete, properties can be tailored to specific needs, thus lowering cement usage and CO2 production. It was found that adding 10 % micro silica reduced the compressive strength at 7 and 28 days, while using 10 % silica sand and 5 % micro silica increased the compressive strength by 14.55 % and 7.79 %, respectively. Exposing specimens to a magnetic field increased compressive strength, with improvements up to 60.36 % for 7-day and 48.02 % for 28-day concrete at 1 T. Incorporating silica sand and micro silica in concrete positively impacts compressive strength under a magnetic field. Silica sand enhances compatibility with additives, improving strength. However, substituting 10 % of cement with micro silica reduces strength due to decreased aggregate adherence. 7-day specimens are more susceptible to magnetic fields than 28-day specimens due to lower displacement in younger samples. This innovative method enables controlled material behavior under magnetic influence. It aims to reduce cement usage while compensating for strength reduction caused by micro silica substitution. The study also determines the minimum magnetic field needed to counteract strength decrease; the aspects which not previously explored.