Journal of Concrete Structures and Materials

Journal of Concrete Structures and Materials

Effect of Curing Duration on the Properties of One-part Alkali-Activated Slag Concrete in an Unsaturated Environment

Document Type : Original Article

Authors
Hamed Zanganeh 1
Ali Sadrmomtazi 2
1 Ph.D. Candidate, Civil Engineering, University of Guilan
2 Professor, Department of Civil Engineering, University of Guilan
10.30478/jcsm.2025.538727.1396
Abstract
This study investigates the effect of curing duration on the properties of one-part alkali-activated slag (O-AAS) concrete and compares its performance with that of ordinary Portland cement (OPC) concrete. The specimens were cured under ambient moist conditions for 1, 7, 28, 56, and 360 days. Following curing, all samples were stored in an environment with 50% relative humidity for up to 360 days. The experimental program included compressive strength, chloride ion diffusion coefficient, free shrinkage, and restrained shrinkage tests. Additionally, core samples were extracted from the center of concrete columns to evaluate compressive strength and chloride ion diffusivity.

The results showed that increasing the ambient moist-curing duration significantly enhanced the performance of O-AAS concrete compared to OPC. Under unsaturated conditions, insufficient curing led to a reduction of up to 37% in the 360-day compressive strength of O-AAS concrete. Extending the curing period from 1 to 7 days reduced free shrinkage by 17.6% and the width of 28-day restrained shrinkage cracks by 60%. Core analysis revealed that inadequate curing resulted in the penetration of microcracks into the inner zones of O-AAS concrete, adversely affecting its mechanical and durability performance. However, increasing the curing duration from 1 to 7 days eliminated the influence of such internal microcracking. In contrast, OPC core specimens exhibited no significant differences in compressive strength and chloride ion diffusion between 1-day, 7-day, and 360-day curing regimes.

Overall, the findings underscore the critical importance of providing adequate early-age curing for O-AAS concrete to ensure long-term durability and mechanical performance, especially in unsaturated environments.
Keywords
One-Part Alkali-Activated Slag Concrete
Chloride Ion Diffusion Coefficient
Curing Duration
Aging
Shrinkage cracking

Subjects

1.  Nasir M, Mahmood AH, Ashraf A, Bahraq AA, (2024). “History, recent progress, and future challenges of alkali-activated binders – An overview”, Constr. Build. Mater., 426, 136141. https://doi.org/10.1016/j.conbuildmat.2024.136141 
2.  Jiang L, Niu Y, Jin W, Gao H, Chen L, (2022). “Influence of chloride salt type on chloride ion diffusion performance of alkali-activated slag mortar”, Constr. Build. Mater., 351, 128930. https://doi.org/10.1016/j.conbuildmat.2022.128930 
3.  Duzy P, Choinska M, Hager I, Amiri O, Claverie J, (2022). “Mechanical Strength and Chloride Ions’ Penetration of Alkali-Activated Concretes (AAC) with Blended Precursor”, Materials, 15(13), 4475. https://doi.org/10.3390/ma15134475 
4.  Elzeadani M, Bompa DV, Elghazouli AY, (2022). “One part alkali activated materials: A state-of-the-art review”, J. Build. Eng., 57, 104871. https://doi.org/10.1016/j.jobe.2022.104871 
5.  Luukkonen T, (2022). “Alkali-Activated Materials in Environmental Technology Applications”, Woodhead Publ. Ser. Civ. Struct. Eng. 
6.  Pacheco-Torgal F, Chindaprasirt P, Ozbakkaloglu T (Eds.), (2021). “Handbook of advances in Alkali-activated Concrete”, 1st Ed., Woodhead Publ. Ser. Civ. Struct. Eng. 
7.  Fu Q, Bu M, Zhang Zh, Xu W, Yuan Q, Niu D, (2023). “Hydration Characteristics and Microstructure of Alkali-Activated Slag Concrete: A Review”, Engineering, 20, 162–179. https://doi.org/10.1016/j.eng.2021.07.026 
8.  Amran M, Onaizi AM, Makul N, Abdelgader HS, Tang WC, Alsulami BT, Alluqmani AE, Gamil Y, (2023). “Shrinkage mitigation in alkali-activated composites: A comprehensive insight into the potential applications for sustainable construction”, Results Eng., 20, 101452. https://doi.org/10.1016/j.rineng.2023.101452 
9.  Sanjuán MA, Muñoz-Martialay R, (1995). “Influence of the age on air permeability of concrete”, J. Mater. Sci., 30(22), 5657–5662. https://doi.org/10.1007/BF00356701 
10. Ogawa Y, Suzuki SH, Kawai K, (2024). “Impact of air exposure post-steam curing on the internal curing efficiency of porous ceramic roof-tile waste fine aggregate in steam-cured fly ash concrete”, Mater. Lett., 366, 136576. https://doi.org/10.1016/j.matlet.2024.136576 
11. Xia H, Lv X, Wang H, Song L, Zhang G, Cao D, Chen H, (2024). “Shrinkage, mechanical properties and freeze-thaw resistance of cement mortar containing internal curing materials with different absorption behaviors at low humidity”, Constr. Build. Mater., 416, 135182. https://doi.org/10.1016/j.conbuildmat.2024.135182 
12. Arayeshgar M, Madandoust R, Ranjbar MM, (2024). “A comparative study on superabsorbent polymer (SAP) and recycled lightweight aggregate (LWA) as internal curing agents for high-strength concrete (HSC)”, Int. J. Eng. Trans. B Appl. 
13. Bažant ZP, Raftshol WJ, (1982). “Effect of cracking in drying and shrinkage specimens”, Cem. Concr. Res., 12(2), 209–226. https://doi.org/10.1016/0008-8846(82)90031-5 
14. Wardhono A, Gunasekara C, Law DW, Setunge S, (2017). “Comparison of long term performance between alkali activated slag and fly ash geopolymer concretes”, Constr. Build. Mater., 143, 272–279. https://doi.org/10.1016/j.conbuildmat.2017.03.153 
15. Collins FG, Sanjayan JG, (2000). “Microcracking and strength development of alkali activated slag concrete”, Cem. Concr. Compos., 23(4–5), 345–352. https://doi.org/10.1016/S0958-9465(01)00003-8 
16. Alhamoud A, Riahi HT, Ataei A, (2024). “Mechanical properties and stress-strain relationship of slag-based one-part geopolymer concrete: A comparative study”, Results Eng., 24, 102952. https://doi.org/10.1016/j.rineng.2024.102952 
17. Prinsse S, Hordijk DA, Ye G, Lagendijk P, Luković M, (2020). “Time-dependent material properties and reinforced beams behavior of two alkali-activated types of concrete”, Struct. Concr., 21(2), 642-658. https://doi.org/10.1002/suco.201900235 
18. El-Hassan H, Shehab E, Al-Sallamin A, (2018). “Influence of Different Curing Regimes on the Performance and Microstructure of Alkali-Activated Slag Concrete”, J. Mater. Civ. Eng., 30(9), 04018230. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002436 
19. Lloyd RR, (2009). “Accelerated ageing of geopolymers”, In: Geopolymers Structures, Processing, Properties and Industrial Applications, Woodhead Publ. Ser. Civ. Struct. Eng. https://doi.org/10.1533/9781845696382.2.139 
20. Yang Q, Wu Y, Zhi P, Zhu P, (2024). “Effect of micro-cracks on chloride ion diffusion in concrete based on stochastic aggregate approach”, Buildings, 14(5), 1353. https://doi.org/10.3390/buildings14051353 
21. ASTM C150, (2017). “Standard specification for Portland Cement”, ASTM Int., Philadelphia, PA. 
22. ASTM C989, (2017). “Standard specification for Slag cement for use in concrete and mortars”, ASTM Int., Philadelphia, PA. 
23. ASTM C33, (2017). “Standard specification for concrete aggregates”, ASTM Int., Philadelphia, PA. 
24. Marvila M.T., Garcez de Azevedo A.R., Linhares Junior J.A.T., Vieira C.M.F., (2023). “Activated alkali cement based on blast furnace slag: effect of curing type and concentration of Na₂O”, J. Mater. Res. Technol., 23, 4551–4565. https://doi.org/10.1016/j.jmrt.2023.02.088
25. ASTM C157, (2017). “Standard test method for length change of hardened cement mortar and concrete”, ASTM Int., Philadelphia, PA. 
26. BS EN 12390-3, (2009). “Testing hardened concrete Part 3: Compressive strength of test Specimens”, BSI, London. 
27. NT Build 492, (1999). “Chloride migration coefficient from Non-steady state migration experiments”, NORDTEST, Finland. 
28. ASTM C596, (2021). “Standard test method for drying shrinkage of mortar containing hydraulic cement”, ASTM Int., Philadelphia, PA. 
29. ASTM C1581, (2024). “Standard test method for determining age at cracking and induced tensile stress characteristics of mortar and concrete under restrained shrinkage”, ASTM Int., Philadelphia, PA. 
30. ASTM C42, (2017). “Standard test method for obtaining and testing drilled cores and sawed beams of concrete”, ASTM Int., Philadelphia, PA. 
31. ASTM C143, (2017). “Standard test method for slump of hydraulic-cement concrete”, ASTM Int., Philadelphia, PA. 
32. Palankar N, Shankar AUR, Mithun BM, (2015). "Air-cured alkali-activated binders for concrete pavements", International Journal of Pavement Research and Technology, 8, 289-294. https://doi.org/10.6135/ijprt.org.tw/2015.8(4).289
33. ASTM C1611, (2021). “Standard test method for slump flow of self-consolidating concrete”, ASTM Int., Philadelphia, PA. 
34. Neville AM, (2008). “Concrete technology”, Pearson Education India. 
35. Bondar D, Ma Q, Soutsos M, Basheer M, Provis JL, Nanukuttan S, (2018). “Alkali activated slag concretes designed for a desired slump, strength and chloride diffusivity”, Constr. Build. Mater., 190, 191–199. https://doi.org/10.1016/j.conbuildmat.2018.09.124 
36. Fan J, Zhu H, Shi J, Li Z, Yang S, (2020). “Influence of slag content on the bond strength, chloride penetration resistance, and interface phase evolution of concrete repaired with alkali activated slag/fly ash”, Constr. Build. Mater., 263, 120639. https://doi.org/10.1016/j.conbuildmat.2020.120639 
37. Hajibabaee A, Moradllo MK, Behravan A, Ley MT, (2018). “Quantitative measurements of curing methods for concrete bridge decks”, Constr. Build. Mater., 162, 306–313. https://doi.org/10.1016/j.conbuildmat.2017.12.023 
38. Zhou S, et al., (2020). “A novel non-Portland cementitious material: Mechanical properties, durability and characterization”, Constr. Build. Mater., 238, 117671. https://doi.org/10.1016/j.conbuildmat.2019.117671 
39. Coppola L, Coffetti D, Crotti E, Candamano S, Crea F, Gazzaniga G, Pastore T, (2021). “The combined use of admixtures for shrinkage reduction in one-part alkali activated slag-based mortars and pastes”, Constr. Build. Mater., 248, 118682. https://doi.org/10.1016/j.conbuildmat.2020.118682 
40. ACI 209.2R-08, (2008). “Guide for Modeling and Calculating Shrinkage and Creep in Hardened Concrete”, ACI, Farmington Hills, MI. 
41. Bagheri AR, Jamali A, Pourmir M, Zanganeh H, (2019). “The influence of curing time on restrained shrinkage cracking of concrete with shrinkage reducing admixture”, Adv. Civ. Eng. Mater., 8(1), 596–610. https://doi.org/10.1520/ACEM20190100 
42. Aiken TA, Kwasny J, Zhou Z, McPolin D, Sha W, (2023). “Factors affecting the drying shrinkage of alkali-activated slag/fly ash mortars”, MRS Adv., 8, 1266–1272. https://doi.org/10.1557/s43580-023-00647-6 
43. Li Z, Wyrzykowski M, Dong H, Granja J, Azenha M, Lura P, Ye G, (2020). “Internal curing by superabsorbent polymers in alkali-activated slag”, Cem. Concr. Res., 135, 106123. https://doi.org/10.1016/j.cemconres.2020.106123

  • Receive Date 02 August 2025
  • Revise Date 14 September 2025
  • Accept Date 25 October 2025