Mechanical behavior and microstructural mechanism of improved disintegrated carbonaceous mudstone

Abstract

This study aims to improve the mechanical behavior of disintegrated carbonaceous mudstone, which is used as road embankment filler in southwestern China. Triaxial tests were performed on disintegrated carbonaceous mudstone modified by fly ash, cement, and red clay. Then the stress-strain relationships and shear strength parameters were analyzed. The microstructure and mineral composition of the materials were identified via scanning electron microscopy and X-ray diffraction. The results show that the stress-strain relationships changed from strain-hardening to strain-softening when disintegrated carbonaceous mudstone was modified with cement. By contrast, the addition of fly ash and red clay did not change the type of stress-strain relationships. The order of these three additives is cement, red clay and fly ash according to their influences on the cohesion. Disintegrated carbonaceous mudstone without cement all showed bulging failures, and that modified with cement exhibited shear failures or bulging-shear failures. The soil particles of the improved soil were well bonded by cementitious substances, so the microstructure was denser and more stable, which highly enhanced the mechanical behavior of disintegrated carbonaceous mudstone. The findings could offer references for the use of carbonaceous mudstone in embankment engineering.

Keywords

embankment engineering / carbonaceous mudstone / additive / mechanical properties / microstructure

References

[1] FuH-y, LiuJ, ZhaH-yi. Study of the strength of disintegrated carbonaceous mudstone modified with nano-AkCb and cement [J]. Journal of Nanoscience and Nanotechnology, 2020, 20(8): 4839-4845

[2] ZENG Ling, YAO Xiao-fei, ZHANG Jun-hui, GAO Qian-feng, CHEN Jing-cheng, GUI Yu-tong. Ponded infiltration and spatial -temporal prediction of the water content of silty mudstone [J]. Bulletin of Engineering Geology and the Environment, 2020: 1–13. DOI: https://doi.org/10.1007/s10064-020-01880-1.

[3] ZengL, LiuJ, GaoQ-f, BianH-bing. Evolution characteristics of the cracks in the completely disintegrated carbonaceous mudstone subjected to cyclic wetting and drying [J]. Advances in Civil Engineering, 2019, 2019: 1279695

[4] ZengL, YaoX-f, GaoQ-f, BianH-b, FanD-hua. Use of nanosilica and cement in improving the mechanical behavior of disintegrated carbonaceous mudstone [J]. Journal of Nanoscience and Nanotechnology, 2020, 20(8): 4807-4814

[5] YinB, KangT-h, KangJ-t, ChenY-juan. Experimental and mechanistic research on enhancing the strength and deformation characteristics of fly-ash-cemented filling materials modified by electrochemical treatment [J]. Energy & Fuels, 2018, 32(3): 3614-3626

[6] YeungA T, GuY Y. A review on techniques to enhance electrochemical remediation of contaminated soils [J]. Journal of Hazardous Materials, 2011, 19511-29

[7] YE Hao, CHU Cheng-fu, XU Long, GUO Kun-long, LI Dong. Experimental studies on drying-wetting cycle characteristics of expansive soils improved by industrial wastes [J]. Advances in Civil Engineering, 2018: 2321361. DOI: https://doi.org/10.1155/2018/2321361.

[8] PhetchuayC, HorpibulsukS, ArulrajahA, SuksiripattanapongC, UdomchaiA. Strength development in soft marine clay stabilized by fly ash and calcium carbide residue based geopolymer [J]. Applied Clay Science, 2016, 127–128: 134-142

[9] PhummiphanI, HorpibulsukS, PhoongernkhamT, ArulrajahA, ShenS-long. Marginal lateritic soil stabilized with calcium carbide residue and fly ash geopolymers as a sustainable pavement base material [J]. Journal of Materials in Civil Engineering, 2017, 29(2): 04016195

[10] ShinawiA E. Instability improvement of the subgrade soils by lime addition at Borg El-Arab, Alexandria, Egypt [J]. Journal of African Earth Sciences, 2017, 130: 195-201

[11] ZengL, XiaoL-y, ZhangJ-h, FuH-yuan. The role of nanotechnology in subgrade and pavement engineering: A review [J]. Journal of Nanoscience and Nanotechnology, 2020, 204607-4618

[12] MaQ-y, GaoC-hui. Effect of basalt fiber on the dynamic mechanical properties of cement-soil in SHPB test [J]. Journal of Materials in Civil Engineering, 2019, 30(8): 04018185

[13] WeiJ Q, MeyerC. Sisal fiber-reinforced cement composite with Portland cement substitution by a combination of metakaolin and nanoclay [J]. Journal of Materials Science, 2014, 49217604-7619

[14] TabarsaA, LatifiN, MeehanC L, ManahilohK N. Laboratory investigation and field evaluation of loess improvement using nanoclay-A sustainable material for construction [J]. Construction and Building Materials, 2018, 158: 454-463

[15] The Professional Standards Compilation Group of People’s Republic of ChinaJTG E40-2007. Test methods of soils for highway engineering [S], 2007, Beijing, China Communications Press(in Chinese)

[16] ZHANG Jun-hui, LI Feng, ZENG Ling, PENG Jun-hui, LI Jue. Numerical simulation of the moisture migration of unsaturated clay embankments in southern China considering stress state [J]. Bulletin of Engineering Geology and the Environment, 2020. DOI: https://doi.org/10.1007/s10064-020-01916-6.

[17] The Professional Standards Compilation Group of People’s Republic of ChinaJTG D30–2015Design standard of highway embankment [S], 2015, Beijing, China Communications Press(in Chinese)

[18] SunY-f, GaoP-w, GengF, LiH-r, ZhangL-f, LiuH-wei. Thermal conductivity and mechanical properties of porous concrete materials [J]. Materials Letters, 2017, 209: 349-352

[19] ZAHNG Jun-hui, PENG Jun-hui, ZENG Ling, LI Jue, LI Feng. Rapid estimation of resilient modulus of subgrade soils using performance-related soil properties [J]. International Journal of Pavement Engineering, 2019: 1–8. DOI: https://doi.org/10.1080/10298436.2019.1643022.

[20] ZAHNG Jun-hui, PENG Jun-hui, LIU Wei-zheng, LU Wei-hua. Predicting resilient modulus of fine-grained subgrade soils considering relative compaction and matric suction [J]. Road Materials and Pavement Design, 2019: 1–13. DOI: https://doi.org/10.1080/14680629.2019.1651756.

[21] GaoQ-f, ZhaoD, ZengL, DongH. A pore size distribution-based microscopic model for evaluating the permeability of clay [J]. KSCE Journal of Civil Engineering, 2019, 23(12): 5002-5011

[22] HynninenA, KulaviirM, KirsimaeK. Air-drying is sufficient pre-treatment for in situ visualization of microbes on minerals with scanning electron microscopy [J]. Journal of Microbiological Methods, 2018, 146: 77-82

[23] GaoQ-f, HattabM, JradM, FleureauJ M, HicherP Y. Microstructural organisation of remoulded clays in relation with dilatancy/contractancy phenomena [J]. Acta Geotechnica, 2020, 15(1): 223-243

[24] GaoQ-f, JradM, HattabM, FleureauJ M, IghilA L. Pore morphology, porosity and pore size distribution in kaolinitic remoulded clays under triaxial loading [J]. International Journal of Geomechanics, 2020, 20(6): 04020057

[25] LoannidouK, KanducM, LiL-n, FrenkelD, DobnikarJ, GadoE D. The crucial effect of early-stage gelation on the mechanical properties of cement hydrates [J]. Nature Communications, 2016, 711-9

[26] DingJ, MaS-h, ZhengS-l, ZhangY, XieZ-l, ShenS R, LiuZ-kai. Study of extracting alumina from high-alumina PC fly ash by a hydro-chemical process [J]. Hydrometallurgy, 2016, 161: 58-64

[27] AhmariS, RenX, ToufighV, ZhangL-yang. Production of geopolymeric binder from blended waste concrete powder and fly ash [J]. Construction and Building Materials, 2012, 35: 718-729

[28] ZhuJ-p, FengC-h, YinH-b, ZhangZ-y, ShahS P. Effects of colloidal nano boehmite and nano SiO₂ on fly ash cement hydration [J]. Construction and Building Materials, 2015, 101: 246-251