Influence of Crack Width on Healing Performance and Mechanical Properties of Micro-Organisms Based Self Healing Concrete

Self healing concrete are the effective methods for solving concrete deterioration and improving durability. Keeping in this view, an experimental study is conducted to evaluate the strength and healing performance of concrete made with 4% fiber for all mixes and Effective Microorganism-1 (Expounded Cracks Healing Agent) of different percentages 0%, 2%, 4% and 6%, 8% and 10%. In this connection, 108 cylinders & 54 cubes of six mixes are prepared. Workability of six mixes lies between 1mm - 38mm which is increasing by the increase of EM-1.The workability of fresh concrete using W/C ratio 0.4 is evaluated. After performing slump test, mix the all ingredients of concrete and cast the cylinders and cubes. Poured cylindrical and cubical specimens are left for different curing ages at 7, 14 and 28 days. After curing, splitting tensile strength test is performed on cylindrical specimens only and compressive strength on hardened concrete cylinders and cubes are tested and then checked the air content ratio of all six mixes which is within the acceptable ranges. After testing the cubes and cylinders are again kept in water for curing to check rate of healing and then checked the microstructure by SEM images. Cracks are small due to the use of fiber addition. By the use of EM-1, cracks can be healed. Maximum healing of crack width is between 0.04 mm to 0.07 mm if cracks width exceeds from 0.20 then it is difficult to restore. Results concluded that microorganism based self healing concrete is suitable at 6% addition in concrete which is suitable for humid environment and hydraulic structures where high strength and voids less concretes are required. Chopped strand mat can be used where concrete can be used without reinforcement.