Effect of blast furnace slag and fly ash on autogenous self-healing in tailings-based cementitious composites

Abstract

The incorporation of supplementary cementitious materials (SCMs), such as blast furnace slag (BFS) and fly ash (FA), provides a promising strategy to optimize cemented paste backfill (CPB) by reducing operational costs, enhancing durability, and reducing the carbon footprint. This study systematically investigates the effects of partially replacing cement with BFS or FA on the autogenous self-healing behavior of the CPB system. Four binder blend ratios (i.e., cement/SCM mass ratio of 100/0, 80/20, 50/50, and 20/80) were evaluated based on crack closure observations, uniaxial compressive strength, hydraulic conductivity, and porosity-related parameters. Results show that the appropriate BFS contents promote self-healing efficiency at early and long-term healing stages compared with cement-only CPB, attributed to the secondary latent hydraulic reactions between BFS and calcium hydroxide, leading to the formation of calcium–(alumino)–silicate–hydrate (C–(A)–S–H) gels and microstructural densification. The pre-cracked Portland cement type I (PCI)/BFS 50/50 specimens exhibited the highest healing efficiency at 28 d of self-healing, with strength exceeding the uncracked control by 17.2% and hydraulic conductivity recovery reaching 81.8%, whereas at 90 d, superior long-term performance was observed for the PCI/BFS 80/20 mixture, achieving a 21.4% strength increase relative to the uncracked control and 96.2% recovery in hydraulic conductivity. In contrast, FA incorporation resulted in progressively reduced self-healing efficiency with increasing FA content due to its intrinsic physical characteristics and delayed pozzolanic reactivity. While the PCI/FA 80/20 mixture recovered strength comparable to the uncracked control, higher FA contents (50/50 and 20/80) exhibited significantly inferior strength recovery (13.3% and 23.2% lower than controls, respectively) and limited hydraulic conductivity recovery. Across both SCM systems, the formation and sufficiency of self-healing products, such as C–(A)–S–H, calcite, and ettringite, primarily govern the overall self-healing performance. These findings provide critical insights for designing CPB with improved autogenous self-healing capacity and optimized binder formulations for field applications.

Keywords

cemented paste backfill / blast furnace slag / fly ash / autogenous self-healing / microstructure / hydraulic conductivity / mechanical strength

References

[1] Wu D, Fall M, Cai SJ. Numerical modelling of thermally and hydraulically coupled processes in hydrating cemented tailings backfill columns. Int. J. Min. Reclam. Environ., 2014, 283173

[2] Ranjith PG, Zhao J, Ju MH, De Silva RVS, Rathnaweera TD, Bandara AKMS. Opportunities and challenges in deep mining: A brief review. Engineering, 2017, 34546

[3] Manzi M, Cooper G, Malehmir A, Durrheim R, Nkosi Z. Integrated interpretation of 3D seismic data to enhance the detection of the gold-bearing reef: Mponeng Gold mine, Witwater-srand Basin (South Africa). Geophys. Prospect., 2015, 634881

[4] R.K. Valenta, É. Lèbre, C. Antonio, et al., Decarbonisation to drive dramatic increase in mining waste-Options for reduction, Reesour. Conserv. Recycl., 190(2023), art. No. 106859.

[5] D.M. Franks, M. Stringer, L.A. Torres-Cruz, et al., Tailings facility disclosures reveal stability risks, Sci. Rep., 11(2021), No. 1, art. No. 5353.

[6] International Council on Mining and Metals (ICMM)United Nations Environment Programme (UNEP)Principles for Responsible Investment (PRI). Global Industry Standard on Tailings Management. 2020[2025-01-20]

[7] Azam S, Li Q. Tailings dam failures: A review of the last one hundred years. Geotech. News, 2010, 28450

[8] Rico M, Benito G, Salgueiro AR, Diez-Herrero A, Pereira HG. Reported tailings dam failures: A review of the European incidents in the worldwide context. J. Hazard. Mater., 2008, 1522846

[9] Z. Al-Moselly, M. Fall, and S. Haruna, Further insight into the strength development of cemented paste backfill materials containing polycarboxylate ether-based superplasticizer, J. Build. Eng., 47(2022), art. No. 103859.

[10] Kratzsch H. Mining Subsidence Engineering. Environ. Geol. Water Sci., 1986, 83133

[11] Sveinson S. Characterisation of Tailings for Paste Backfill System Design. 1999, City, University of British Columbia

[12] Grice T. Underground mining with backfill. 2nd Annual Summit—Mine Tailings Disposal Systems. 19981

[13] Fall M, Benzaazoua M. Modeling the effect of sulphate on strength development of paste backfill and binder mixture optimization. Cem. Concr. Res., 2005, 352301

[14] Kesimal A, Yilmaz E, Ercikdi B, Alp I, Deveci H. Effect of properties of tailings and binder on the short-and long-term strength and stability of cemented paste backfill. Mater. Lett., 2005, 59283703

[15] C.C. Qi and A. Fourie, Cemented paste backfill for mineral tailings management: Review and future perspectives, Miner. Eng., 144(2019), art. No. 106025.

[16] Fall M, Adrien D, Célestin JC, Pokharel M, Touré M. Saturated hydraulic conductivity of cemented paste backfill. Miner. Eng., 2009, 22151307

[17] Hassani F, Razavi SM, Isagon I. A study of physical and mechanical behaviour of gelfill. CM Bull., 2008, 100209

[18] Ercikdi B, Kesimal A, Cihangir F, Deveci H, Alp I. Cemented paste backfill of sulphide-rich tailings: Importance of binder type and dosage. Cem. Concr. Compos., 2009, 314268

[19] Fall M, Pokharel M. Coupled effects of sulphate and temperature on the strength development of cemented tailings backfills: Portland cement-paste backfill. Cem. Concr. Compos., 2010, 3210819

[20] Damtoft JS, Lukasik J, Herfort D, Sorrentino D, Gartner EM. Sustainable development and climate change initiatives. Cem. Concr. Res., 2008, 382115

[21] O.E. Ogunmakinde, T. Egbelakin, and W. Sher, Contributions of the circular economy to the UN sustainable development goals through sustainable construction, Resour. Conserv. Recycl., 178(2022), art. No. 106023.

[22] Sinsiri T, Chindaprasirt P, Jaturapitakkul C. Influence of fly ash fineness and shape on the porosity and permeability of blended cement pastes. Int. J. Miner. Metall. Mater., 2010, 176683

[23] S.K. Behera, C.N. Ghosh, K. Mishra, et al., Utilisation of lead-zinc mill tailings and slag as paste backfill materials, Environ. Earth Sci., 79(2020), No. 16, art. No. 389.

[24] S.K. Behera, D.P. Mishra, P. Singh, et al., Utilization of mill tailings, fly ash and slag as mine paste backfill material: Review and future perspective, Constr. Build. Mater., 309(2021), art. No. 125120.

[25] Kar KK. Handbook of Fly Ash. 2021

[26] S.K. Behera, C.N. Ghosh, D.P. Mishra, et al, Strength development and microstructural investigation of lead-zinc mill tailings based paste backfill with fly ash as alternative binder, Cem. Concr. Compos., 109(2020), art. No. 103553.

[27] Xiao BL, Fall M, Roshani A. Towards understanding the rheological properties of slag-cemented paste backfill. Int. J. Min. Reclam. Environ., 2021, 354268

[28] Li WC, Fall M. Strength and self-desiccation of slag-cemented paste backfill at early ages: Link to initial sulphate concentration. Cem. Concr. Compos., 2018, 89160

[29] Jiang HQ, Han J, Li YH, Yilmaz E, Sun Q, Liu JP. Relationship between ultrasonic pulse velocity and uniaxial compressive strength for cemented paste backfill with alkali-activated slag. Nondestruct. Test. Eval., 2020, 354359

[30] Yilmaz E, Belem T, Bussière B, Benzaazoua M. Relationships between microstructural properties and compressive strength of consolidated and unconsolidated cemented paste backfills. Cem. Concr. Compos., 2011, 336702

[31] Yilmaz E, Belem T, Benzaazoua M, Kesimal A, Ercikdi B, Cihangir F. Use of high-density paste bacfill for safe disposal of copper/zinc mine tailings. Gospodarka Surowcami Mineralnymi-Mineral Resources Management, 2011, 27381

[32] Arachchilage CB, Fan CK, Zhao J, Huang GP, Liu WV. A machine learning model to predict unconfined compressive strength of alkali-activated slag-based cemented paste backfill. J. Rock Mech. Geotech. Eng., 2023, 15112803

[33] N. Zhou, C.W. Dong, J.X. Zhang, G.H. Meng, and Q.Q. Cheng, Influences of mine water on the properties of construction and demolition waste-based cemented paste backfill, Constr. Build. Mater., 313(2021), art. No. 125492.

[34] Zhao Y, Taheri A, Karakus M, Chen ZW, Deng A. Effects of water content, water type and temperature on the rheological behaviour of slag-cement and fly ash-cement paste backfill. Int. J. Min. Sci. Technol., 2020, 303271

[35] Qi TY, Feng GR, Zhang YJ, Guo J, Guo YX. Effects of fly ash content on properties of cement paste backfilling. J. Residuals Sci. Technol., 2015, 123133

[36] H.Q. Jiang, H.S. Yi, E. Yilmaz, S.W. Liu, and J.P. Qiu, Ultrasonic evaluation of strength properties of cemented paste backfill: Effects of mineral admixture and curing temperature, Ultrasonics, 100(2020), art. No. 105983.

[37] Klein K, Simon D. Effect of specimen composition on the strength development in cemented paste backfill. Can. Geotech. J., 2006, 433310

[38] W.Z. Quan and M. Fall, Investigation of crack self-healing behaviour and its impact on strength and permeability recovery in cemented paste tailings, Powder Technol., 457(2025), art. No. 120834.

[39] W.Z. Quan and M. Fall, Temperature-driven crack self-healing and performance recovery in cemented tailings materials, Case Stud. Constr. Mater., 21(2024), art. No. e04105.

[40] W.Z. Quan and M. Fall, Self-healing responses of cementitious tailings materials to changing drainage conditions, Dev. Built Environ., 22(2025), art. No. 100648.

[41] Thomas M. Optimizing the Use of Fly Ash in Concrete. 2007, Skokie, Portland Cement Association

[42] Termkhajornkit P, Nawa T, Yamashiro Y, Saito T. Self-healing ability of fly ash-cement systems. Cem. Concr. Compos., 2009, 313195

[43] Huang HL, Ye G, Damidot D. Effect of blast furnace slag on self-healing of microcracks in cementitious materials. Cem. Concr. Res., 2014, 6068

[44] Nguyen HH, Choi JI, Song KI, Song JK, Huh J, Lee BY. Self-healing properties of cement-based and alkali-activated slag-based fiber-reinforced composites. Constr. Build. Mater., 2018, 165801

[45] Darquennes A, Olivier K, Benboudjema F, Gagné R. Self-healing at early-age, a way to improve the chloride resistance of blast-furnace slag cementitious materials. Constr. Build. Mater., 2016, 1131017

[46] Burciaga-Díaz O, Betancourt-Castillo I. Characterization of novel blast-furnace slag cement pastes and mortars activated with a reactive mixture of MgO–NaOH. Cem. Concr. Res., 2018, 10554

[47] ASTM International. ASTM Standard C39/C39M-21: Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. 2021, West Conshohocken, ASTM International

[48] ASTM International. ASTM Standard D5084-16a: Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter. 2016, West Conshohocken, ASTM International

[49] ASTM International. ASTM Standard D854-23: Standard Test Methods for Specific Gravity of Soil Solids by the Water Displacement Method. 2023, West Conshohocken, ASTM International

[50] Manmohan D, Mehta PK. Influence of pozzolanic, slag, and chemical admixtures on pore size distribution and permeability of hardened cement pastes. Cem. Concr. Aggreg., 1981, 3163

[51] Escalante JI, Gómez LY, Johal KK, Mendoza G, Mancha H, Méndez J. Reactivity of blast-furnace slag in Portland cement blends hydrated under different conditions. Cem. Concr. Res., 2001, 31101403

[52] Pokharel M, Fall M. Coupled thermochemical effects on the strength development of slag-paste backfill materials. J. Mater. Civ. Eng., 2011, 235511

[53] D. Xu, D.J. Zhang, D.M. Wang, and G.D. Qi, Effects of GGBFS on hydration and carbonation process, microstructure, and mechanical properties of NHL-based materials, J. Build. Eng., 60(2022), art. No. 105149.

[54] Lim SN, Wee TH. Autogenous shrinkage of ground-granulated blast-furnace slag concrete. Mater. J., 2000, 975587

[55] Bijen J. Benefits of slag and fly ash. Constr. Build. Mater., 1996, 105309

[56] Ghirian A, Fall M. Coupled behavior of cemented paste backfill at early ages. Geotech. Geol. Eng., 2015, 3351141

[57] Hewlett P, Liska M. Lea’s Chemistry of Cement and Concrete. 20195th ed.

[58] Taylor HFW. Cement Chemistry. 19972nd ed.London, Thomas Telford

[59] Bhatty JI. A review of the application of thermal analysis to cement-admixture systems. Thermochim. Acta, 1991, 1892313

[60] Pane I, Hansen W. Investigation of blended cement hydration by isothermal calorimetry and thermal analysis. Cem. Concr. Res., 2005, 3561155

[61] G. Ali, M. Fall, and I. Alainachi, Time- and temperature-dependence of rheological properties of cemented tailings backfill with sodium silicate, J. Mater. Civ. Eng., 33(2021), No. 3, art. No. 04020498.

[62] Mojid MA. Diffuse double layer (DDL). Encyclopedia of Agrophysics. 2011, Netherlands, Springer213

[63] Nägele E. The zeta-potential of cement part II: Effect of pH-value. Cem. Concr. Res., 1986, 166853

[64] B.B. Sun, G. Ye, and G. de Schutter, A review: Reaction mechanism and strength of slag and fly ash-based alkali-activated materials, Constr. Build. Mater., 326(2022), art. No. 126843.

[65] Ye HL, Radlinska A. Fly ash-slag interaction during alkaline activation: Influence of activators on phase assemblage and microstructure formation. Constr. Build. Mater., 2016, 122594

[66] Bisschop J, Wittel FK. Contraction gradient induced microcracking in hardened cement paste. Cem. Concr. Compos., 2011, 334466

[67] Niu QL, Feng NQ, Yang J, Zheng XY. Effect of superfine slag powder on cement properties. Cem. Concr. Res., 2002, 324615

[68] Sohn HY, Moreland C. The effect of particle size distribution on packing density. Can. J. Chem. Eng., 1968, 463162

[69] Y. Briki, M. Zajac, M. Ben Haha, and K. Scrivener, Factors affecting the reactivity of slag at early and late ages, Cem. Concr. Res., 150(2021), art. No. 106604.

[70] Wang XY. Effect of fly ash on properties evolution of cement based materials. Constr. Build. Mater., 2014, 6932

[71] Biernacki JJ, Williams PJ, Stutzman PE. Kinetics of reaction of calcium hydroxide and fly ash. ACI Mater. J., 2001, 984340

[72] Narmluk M, Nawa T. Effect of fly ash on the kinetics of Portland cement hydration at different curing temperatures. Cem. Concr. Res., 2011, 416579

[73] Sakai E, Miyahara S, Ohsawa S, Lee SH, Daimon M. Hydration of fly ash cement. Cem. Concr. Res., 2005, 3561135

[74] Akmalaiuly K, Berdikul N, Pundienė I, Pranckevičienė J. The effect of mechanical activation of fly ash on cement-based materials hydration and hardened state properties. Materials, 2023, 1682959

[75] Takemoto K, Uchikawa H. Hydration of pozzolanic cements. Proceedings of 7th International Congress on the Chemistry of Cements. 19801

[76] Xu A, Sarkar SL, Nilsson LO. Effect of fly ash on the microstructure of cement mortar. Mater. Struct., 1993, 267414

[77] P. Chindasiriphan, H. Yokota, and P. Pimpakan, Effect of fly ash and superabsorbent polymer on concrete self-healing ability, Constr. Build. Mater., 233(2020), art. No. 116975.

[78] Zhang ZG, Qian SZ, Ma H. Investigating mechanical properties and self-healing behavior of micro-cracked ECC with different volume of fly ash. Constr. Build. Mater., 2014, 5217

[79] Sahmaran M, Yildirim G, Erdem TK. Self-healing capability of cementitious composites incorporating different supplementary cementitious materials. Cem. Concr. Compos., 2013, 35189

[80] Benzaazoua M, Fall M, Belem T. A contribution to understanding the hardening process of cemented pastefill. Miner. Eng., 2004, 172141

[81] Bentz DP, Peltz MA, Winpigler J. Early-age properties of cement-based materials. II: Influence of water-to-cement ratio. J. Mater. Civ. Eng., 2009, 219512

[82] Sisomphon K, Copuroglu O, Koenders EAB. Self-healing of surface cracks in mortars with expansive additive and crystalline additive. Cem. Concr. Compos., 2012, 344566

[83] J.N. Sun, K.H. Kong, C.Q. Lye, and S.T. Quek, Effect of ground granulated blast furnace slag on cement hydration and autogenous healing of concrete, Constr. Build. Mater., 315(2022), art. No. 125365.

[84] Y.F. Hu, R.P. Hu, B. Zhang, and B. Han, Research on mechanical properties and mix proportion design of solid waste-based cemented paste backfill, Case Stud. Constr. Mater., 21(2024), art. No. e03618.

[85] Y.B. Feng, W.Y. Qi, Q.X. Zhao, et al., Synthesis and characterization of cemented paste backfill: Reuse of multiple solid wastes, J. Cleaner Prod., 383(2023), art. No. 135376.

[86] Wang CL, Ren ZZ, Huo ZK, et al. . Properties and hydration characteristics of mine cemented paste backfill material containing secondary smelting water-granulated nickel slag. Alex. Eng. J., 2021, 6064961

[87] M. Sari, E. Yilmaz, and T. Kasap, Long-term ageing characteristics of cemented paste backfill: Usability of sand as a partial substitute of hazardous tailings, J. Cleaner Prod., 401(2023), art. No. 136723.

[88] X.G. Sun, J. Liu, J.P. Qiu, P.Q. Wu, and Y.Q. Zhao, Alkali activation of blast furnace slag using a carbonate-calcium carbide residue alkaline mixture to prepare cemented paste backfill, Constr. Build. Mater., 320(2022), art. No. 126234.

[89] F.W. Zhang, Y.Y. Li, J.H. Zhang, X. Gui, X.H. Zhu, and C.M. Zhao, Effects of slag-based cementitious material on the mechanical behavior and heavy metal immobilization of mine tailings based cemented paste backfill, Heliyon, 8(2022), No. 9, art. No. e10695.

[90] Fall M, Célestin JC, Pokharel M, Touré M. A contribution to understanding the effects of curing temperature on the mechanical properties of mine cemented tailings backfill. Eng. Geol., 2010, 1143–4397

[91] Maltais Y, Marchand J. Influence of curing temperature on cement hydration and mechanical strength development of fly ash mortars. Cem. Concr. Res., 1997, 2771009

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