International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 09 Issue: 06 | Jun 2022 www.irjet.net p-ISSN: 2395-0072 © 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1227 Self-healing Concrete Shital Wani 1 , Shubham Ghuge 2 , Sayali Kadam 3 , Snehal Gulve 4 1 Assistant Professor, Dept. of Civil Enginerring K. K. Wagh Institue of Engineering Education and Research, Nashik 234 UG Student, Dept. of Civil Enginerring K. K. Wagh Institue of Engineering Education and Research, Nashik ---------------------------------------------------------------------***-------------------------------------------------------------------- Abstract- Crack formation is very common phenomenon in concrete structure which allows water and different types of chemicals into concrete through the cracks and decreases durability, strength & affects the reinforcement. Due to this negative impact of construction processes on environment and a decrease in investment, there is a need for concrete structures to operate longer while maintaining their high performance. Self- healing concrete has the ability to heal itself when it is cracked, thereby protects the interior matrix as well as reinforcement steel, resulting in increased service life. By introducing Bacteria in concrete, it produces calcium carbonate crystals which block the micro cracks and pores in the concrete. After studying research papers, it was observed that bacteria improve the structural properties such as tensile strength, water permeability, durability, compressive strength of the normal concrete which was found by performing different type of experiment on specimen. Compressive strength of the concrete was tested by casting specimens of M-25 concrete grade and performing significant tests on them with sets of specimens having different curing time. Study for ideal percentage of concrete was also done which can give best results for compressive strength of concrete. Self -healing concrete was observed the best solution for the demand of sustainable concrete due to its ability of self-repair and durability. Self -healing efficiency on concrete of M-25 grade was observed satisfying during the experiment. Cracks were sufficiently healed during the observation period after adding the bacterial paste of bacillus subtillis and water Key Words: Bacillus subtillis, M-25 Concrete grade, 1.INTRODUCTION Concrete which forms major components in the construction industry as it is cheap, easily available and convenient to cast. But drawback of these materials is it is weak in tension so, it cracks under sustained loading and due to aggressive environmental agents, which ultimately reduce the life of the structure which are built using these materials. This process of damage occurs in the early life of the building structure and also during its life time. Synthetic materials like epoxies are used for remediation. But they are not compatible, costly, reducing aesthetic appearance and need constant maintenance. Therefore, bacterial induced calcium carbonate (calcite) precipitation has been proposed as an alternative and environment friendly crack remediation and hence improvement of strength of building materials 1.1 PROBLEM STATEMENT  Reduced efficiency of a structure due to developed cracks  High maintenance cost after generation of cracks 1.2 OBJECTIVES  To study various self-healing methods for concrete structures  To increase the efficiency of a structure by introducing self-healing mechanism  To check the efficiency of bacillus subtilis as a self-healing property on M-25 grade of concrete  To reduce the repairing cost and to increase the life span of the structure 2. REVIEW OF LITERATURE 2.1 Carola Edvardsen, et, al. (1999) The experimental studies showed the formation of calcite in the crack to be almost the sole cause for the autogenously healing. The crystal growth rate is dependent on the crack width and water pressure, whereas concrete composition and water hardness have no influence on autogenously healing 2.2 Jashir bashir, et, al. (2016) In this study M 20 Concrete grade was studied for various properties of self healing concrete using 3 bacteria namely Bacillus Subtilis, Bacillus Sphaericus, Bacillus pasteurii and the results were compared. 2.3 Xin wang, et, al. (2017) In this study, a new type of cement-based healing pellets (CHPs) were proposed to accelerate the healing efficiency of concrete, which was mainly based on the introduced Na2CO3 on promoting the formation of calcium carbonate (CaCO3) in cracks.. 2.4 Roli verma, et, al. (2018) In this study they observed the Self Healing Concrete has comparatively very less permeability, more durability and strain bearing capacity than the conventional concrete. While most healing agents are chemically based, more recently the possible application of bacteria as self-healing agent has also been considered.