EICP Cemented Sand Modified with Biopolymer

Abstract

Urbanization growth in the world in past two decades are considered a challenge in terms of supplying required construction building materials needed for this development. Bricks are an important construction material that consumes energy, aggregates and cement during their manufacturing. Cement, widely used binder to manufacture brick, is responsible for producing around 5% of manmade CO2 emissions. This research investigates development of a natural bio-cemented sandstone that can be used as a green-bricks. In this approach, urease enzyme will be used to catalyze hydrolysis of urea in presence of calcium to introduce carbonate precipitation that binds Silica sand particles through a process called Enzyme Induced Carbonate Precipitation (EICP). Sodium alginate (SA) biopolymer was used to enhance the performance of the EICP cementation process by promoting carbonate precipitation around sand particles. Different percentages of SA were used to optimize the cementing solution concentrations and come up with a preferred solution for brick manufacturing. Four-point flexural tests and unconfined compression test are used to demonstrate the performance of the proposed approach and to assess its feasibility after curing time of 7 days. Results show these proposed bio-blocks can have strengths ranging from 1 MPa to 2 MPa. Bio-blocks are comparable in terms of stress and stiffness to bricks prepared with cement conventionally used in the block construction.