Title:
Drying Shrinkage in Alkali Activated Class C Fly Ash Mortars and the Mitigation Methods
Author(s):
Darshan Ballekere Kumarappa, Chathurani Chandrasiri and Sulapha Peethamparan
Publication:
Symposium Paper
Volume:
320
Issue:
Appears on pages(s):
10.1-10.12
Keywords:
alkali-activated class C fly ash, drying shrinkage, alkaline activator, internal curing, polypropylene fibers
DOI:
10.14359/51701048
Date:
8/1/2017
Abstract:
The drying shrinkage of alkali activated class C fly ash (FAC) is quantified in this study in accordance with ASTM C490. The effect of activator concentration is evaluated by varying silica modulus (SiO2/Na2O) and Na2O contents. An ordinary portland cement (OPC) mortar mixture is also evaluated for the comparison purposes. In general, drying shrinkage is significantly higher in FAC mortars than in OPC mortar. Higher amounts of both silica modulus and Na2O contents result in greater drying shrinkage. Hydration kinetics and porosity are also evaluated to describe the higher drying shrinkage exhibited by FAC mortars. FAC mortars with a larger drying
shrinkage exhibited a lower mass loss, a reverse trend normally exhibited by OPC mortars. Internal curing and
discrete polypropylene fiber addition are evaluated as potential shrinkage reducing methods. The results show that both methods are efficient in reducing the drying shrinkage in FAC mortars.
Related References:
1. Holt, E.E., 2001, “Early Age Autogenous Shrinkage of Concrete”, Technical Research Centre of Finland.
2. Li, J., Yao, Y., 2001, “A study on creep and drying shrinkage of high performance concrete”, Cement and Concrete Research, 31, 1203-1206.
3. Bakharev, T., Sanjayan, J.G., Cheng, Y. 1999, “Alkali activation of Australian slag cements”, Cement and Concrete Research, 29, 113-120.
4. Atis, C.D., Bilim, C., Çelik, Ö., Karahan, O., 2009, “Influence of activator on the strength and drying shrinkage of alkali-activated slag mortar”, Construction Building Materials, 23, 548-555.
5. Ballekere Kumarappa D., Peethamparan, S., 2017 “Quantification of Drying Shrinkage in Alkali-Activated Slag Mortars and Validating the Efficiency of Various Shrinkage Mitigation Methods”, Transportation Research Board 96th Annual Meeting, No. 17-04788.
6. Wang, S., Pu, X., Scrivener, K., Pratt, P., 1995, “Alkali-activated slag cement and concrete: a review of properties and problems”, Advances in cement research, 7, 93-102.
7. Collins, F., Sanjayan, J., 2001, “Microcracking and strength development of alkali activated slag concrete”, Cement and Concrete Composites, 23, 345-352.
8. Krizan, D., Zivanovic, B., 2002, “Effects of dosage and modulus of water glass on early hydration of alkali–slag cements”, Cement and Concrete Research, 32, 1181-1188.
9. Collins, F., Sanjayan, J.G., 1999, “Strength and shrinkage properties of alkali-activated slag concrete containing porous coarse aggregate”, Cement and Concrete Research, 29 607-610.
10. Naik, T.R., Chun, Y., Kraus, R.N, 2007, “Shrinkage of concrete with and without fly ash”.
11. Chindaprasirt, P., Homwuttiwong, S., Sirivivatnanon, V., 2004, “Influence of fly ash fineness on strength, drying shrinkage and sulfate resistance of blended cement mortar”, Cement and Concrete Research, 34, 1087-1092.
12. Ma, Y., Ye, G., 2015, “The shrinkage of alkali activated fly ash”, Cement and Concrete Research, 68, 75-82.
13. Hardjito, D., Wallah, S.E., Sumajouw, D.M., Rangan, B.V., 2004 “On the development of fly ash-based geopolymer concrete”, ACI Materials Journal-American Concrete Institute, 101, 467-472.
14. Fernandez-Jimenez, A.M., Palomo, A., Lopez-Hombrados, C., 2006, “Engineering properties of alkaliactivated fly ash concrete”, ACI Materials Journal, 103, 106-112.
15. De la Varga, I., Castro, J., Bentz, D., Weiss, J., 2012, “Application of internal curing for mixtures containing high volumes of fly ash”, Cement and Concrete Composites, 34, 1001-1008.
16. Sakulich, A.R., Bentz, D.P., 2013, “Mitigation of autogenous shrinkage in alkali activated slag mortars by internal curing”, Material Structures, 46, 1355-1367.
17. Voigt, T., Bui, V.K., Shah, S.P., 2004, “Drying shrinkage of concrete reinforced with fibers and welded-wire fabric”, Materials Journal, 101, 233-241.
18. Aydin, S., Baradan, B., 2013, “The effect of fiber properties on high performance alkali-activated slag/silica fume mortars”, Composites Part B: Engineering, 45, 63-69.
19. Puertas, F., Amat, T., Fernández-Jiménez, A., Vázquez, T., 2003, “Mechanical and durable behaviour of alkaline cement mortars reinforced with polypropylene fibres”, Cement and Concrete Research, 33, 2031-2036.
20. ASTM C490- 01: Standard Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete, 2001, ASTM International.
21. ASTM C778- 02: Standard Specification for Standard Sand, ASTM International.
22. Safiuddin, Md., Hearn, N., 2005, “Comparison of ASTM saturation techniques for measuring the permeable porosity of concrete”, Cement and Concrete Research, 35, 1008-1013.
23. Palomo, A., Grutzeck, M., Blanco, M., 1999, “Alkali-activated fly ashes: a cement for the future”, Cement and Concrete Research, 29, 1323-1329.
24. Deir, E., Gebregziabiher, B.S., Peethamparan, S., 2014, “Influence of starting material on the early age hydration kinetics, microstructure and composition of binding gel in alkali activated binder systems”, Cement and Concrete Composites, 48, 108-117.
25. Fernández-Jiménez, A., Palomo, A., Sobrados, I., Sanz, J., 2006, “The role played by the reactive alumina content in the alkaline activation of fly ashes”, Microporous and Mesoporous materials, 91, 111-119.
26. Shi, C., Day, R.L., 1995, “A calorimetric study of early hydration of alkali-slag cements”, Cement and Concrete Research, 25, 1333-1346.
27. Lura, P., Jensen, O.M., Van Breugel, K., 2003, “Autogenous shrinkage in high-performance cement paste: an evaluation of basic mechanisms”, Cement and Concrete Research, 33, 223-232.
28. Thomas, J.J., Allen, A.J., Jennings, H.M., 2012, “Density and water content of nanoscale solid C–S–H formed in alkali-activated slag (AAS) paste and implications for chemical shrinkage”, Cement and Concrete Research, 42, 377-383.
29. Arisoy, B., 2002, “Development and fracture evaluation of high performance fiber reinforced lightweight concrete” Ph. D. thesis., Detroit, MI, USA: Wayne State University.
30. Vaidya, S., Allouche, E.N., 2011, “Strain sensing of carbon fiber reinforced geopolymer concrete”, Material Structures, 44, 1467-1475.