Document Type : Research Article
Department of Civil Engineering, Borujerd Branch, Islamic Azad University, Borujerd, Iran
Faculty of civil engineering Borujrd branch Islamic Azad University
Today, the production of lightweight concrete is developing. Microbial calcite precipitation induction is known as a new environmentally friendly strategy. Although the main goal of developing the biological concrete has been cracked healing, achieving this goal not only must be without negative effects on the mechanical properties and durability of concrete but also through knowing and testing the key effective parameters, a biological concrete with the ideal engineering properties can be obtained that is distinguished among the other typical kinds of concrete. In this study, to produce lightweight concrete with desirable durability and resistance, the technique of using bacteria in concrete has been enjoyed. Small concrete pores, an alkaline environment, inaccessibility to nutrients, and enough oxygen are the basic challenges of using biological minerals in concrete. Therefore, the air-entrained has been used as a protective approach to enhance bacteria durability and preserve colonies. The results of the tests conducted show that Calcium carbonate precipitation resulting from the metabolic activity of microorganisms has resulted in the increase of mechanical properties and improved durability of lightweight concrete. Also, air-entrained as an effective factor has had a fundamental role in preserving durability and improving bacteria performance. The use of bacteria in concrete has led to an increase of 19.8% in compressive strength and 63.9% in electrical resistance. Also, the maximum reduction of water absorption and reduction of chloride ion penetration in the biological sample was 62.7% and 40.7%, respectively.