Summary

Cement is a one of a best engineering material due to its higher strength, durability and workability and widely used in the geotechnical engineering field mainly as a grouting material to stabilize the slope surface. However, cement contributes to the CO2 emission hugely and indirectly to the global warming and several other environmental issues. Due to these reasons, cement becomes a less sustainable and noneco- friendly material. Therefore, in this research, novel, eco-friendly and sustainable bio-cementing material is proposed mainly for the stabilization of the slope surface by polymer modified microbial induced carbonate precipitation.
Microbial induced carbonate precipitation (MICP) is a biogeochemical process which is catalyzed by the enzyme urease. Urease has a capability to hydrolysis urea and produce carbonate ions. Then, in the presence of the calcium ions CaCO3bio-cement can be produced. The efficiency of the process can be further improved by adding biopolymers and the process is called as polymer modified MICP. In this research, first time in Sri Lanka, proposing a novel bio-grouting material using polymer modified MICP for slope surface stabilization. Further, this study aims to analyze the effects of the cationic and anionic biopolymer modified MICP on soil densification and slope surface protection by using locally isolated bacterium. If this research is succeeded, it will be a new era of the Sri Lankan geotechnical engineering field and hopefully to build up collaborations with the geotechnical engineering companies in Sri Lanka to promote and apply this concept to mitigate the slope failures in Sri Lanka.

Objectives

• The aim of the study is to produce a novel, ecofriendly and sustainable bio-cementing material using
  polymer modified MICP method for the slope surface stabilization.
  In order to attain the aim of the study, the following objectives are formulated
  1. Identified a landslide prone area in Sri Lanka and isolation of a ureolitic bacteria from that area.
  2. Investigate the urease activity, CaCO3 production efficiency of the isolated bacteria
  3. Investigate the CaCO3 production efficiency in the presence of cationic and anionic natural
  polysaccharide.
  4. Conduct laboratory scale experiments to check the effect of the MICP treated with cationic and
  anionic polysaccharide on soil densification and analyze the durability.
  5. Check the effectiveness of the produced bio-cement on the slope surface stabilization using
  laboratory scaled slope model.
  6. Apply the bio-cement for the identified real slope and investigate the efficiency.

Major Equipment Facilitated by Grant