Bio-mediated calcium carbonate precipitation and its effect on the shear behaviour of calcareous sand
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RESEARCH PAPER
Bio-mediated calcium carbonate precipitation and its effect on the shear behaviour of calcareous sand Ming-Juan Cui1 • Jun-Jie Zheng1
•
Jian Chu2 • Chao-Chuan Wu1 • Han-Jiang Lai2
Received: 29 January 2020 / Accepted: 15 October 2020 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Calcareous sands have abundant intraparticle pores and are prone to particle breakage. This often leads to poor engineering properties, which poses a challenge to coastal infrastructure construction. A study using bio-cementation to improve the engineering properties of calcareous sand is presented in this paper. The macro- and microscopic properties of biocemented calcareous sand were characterized by drained triaxial tests and scanning electron microscopy observations. Experimental results show that the precipitated calcium carbonate can effectively fill the intra- and interparticle pores and bond adjacent particles, thus enhancing the shear strength of calcareous sand. The special structures (e.g. abundant intraparticle pores and rough surface) and mineral components (i.e. calcium carbonate) of calcareous sand are beneficial for improving bacterial retention in soil, which leads to a relatively uniform and dense calcium carbonate distribution on the sand particle surface, exhibiting a layer-by-layer growth pattern. This growth pattern and the abundant interparticle pores would result in less effective calcium carbonate. The strength enhancement of bio-cemented calcareous sand is significantly lower than that of bio-cemented silica sand at the same calcium carbonate content, which may be caused by the differences in the following: (a) soil skeleton strength; (b) the amount of effective calcium carbonate; and (c) interparticle pore-filling of calcium carbonate. Keywords Bio-cementation Calcareous sand Calcium carbonate precipitation Shear behaviour Strength enhancement
1 Introduction Calcareous sands are widespread in coastal areas. Particle breakage, which is regarded as one of the most typical characteristics of calcareous sand [16, 45, 54], often leads to poor engineering properties, which poses a challenge to coastal infrastructure construction [48]. As the strength and stress–strain behaviour of calcareous sand are greatly affected by crushing or particle breakage [24], the engineering properties of calcareous sand significantly differ from those of silica sand because of the aforementioned
& Jun-Jie Zheng [email protected] 1
Institute of Geotechnical and Underground Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
2
School of Civil and Environmental Engineering, Nanyang Technological University, 10 Blk N1, 50 Nanyang Ave, Singapore 639798, Singapore
crushability [2]. Several methods have been adopted in the past to improve the engineering properties of calcareous sands. Rezvani [42] and Goodarzi and Shahnazari [22] reported that geotextiles contribute to increasing the peak strength of calcareous sa
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