Production and Analysis of Sporosarcina pasteurii Biocement Bricks Using Custom 3D-Printed Molds for Unconfined Compression Tests.

Abstract

Cement is a key building material used in many structures across the globe, from foundations for homes to historical monuments and roadways. It is a critical and abundant material worldwide. However, the traditional production of cement is a major contributor to man-made atmospheric CO2, leading to greenhouse gas emissions and climate change. Microbially induced calcite precipitation (MICP) is a biological process in which Sporosarcina pasteurii or other bacteria produce a cement material that is as strong as traditional cement, but biocement is carbon-neutral. This MICP method of producing biocement is a promising technology and is currently under active investigation by many companies, countries, and research groups. The protocol presented here employs custom-designed, reusable, 3D-printed molds for flow-through MICP treatment of soil or sand, producing cylindrical bricks that meet standard specifications for unconfined compression tests. The individual, free-standing, reservoir-topped molds allow convenient parallel testing of multiple variables and replicates. This protocol outlines the S. pasteurii MICP reaction and the creation, assembly, and use of the 3D-printed molds to generate biocement cylindrical bricks.