Title:
Superplasticizers for Calcined Clay Blended Cements
Author(s):
Ran Li, Marlene Schmidt, Tongbo Sui, Johann Plank
Publication:
Symposium Paper
Volume:
355
Issue:
Appears on pages(s):
69-80
Keywords:
Polycarboxylate; superplasticizer; composite cement; calcined clay; metakaolin; workability; slump retention
DOI:
10.14359/51736013
Date:
7/1/2022
Abstract:
In this study, the behavior of a calcined mixed clay (CMC) exhibiting a particularly high metakaolin content (~51 %) in composite cements (substitution rates 0–50 wt. %) was studied. It was found that CMC much decreases workability and substantially increases the water demand due to its higher fineness as compared to OPC. Furthermore, the water demand of pure calcined clays was investigated, and the order as follows was established: meta muscovite ≫ meta illite ≫ metakaolin > meta montmorillonite. Additionally, the dispersing effectiveness of a series of precast-type PCEs selected from the groups of MPEG, HPEG, and IPEG polymers was tested in blended cements holding 0–50 wt. % of the CMC. According to this, the HPEG PCE disperses these composite cements best, followed by the IPEG and the MPEG PCEs. Generally, the presence of CMC prompts significantly higher PCE dosages (up to 800 % more for the 50:50 OPC/CC blend). Furthermore, it was found that in OPC/CMC blended cements slump retention is much more difficult to achieve than in OPC. As such, an industrial ready-mix type HPEG PCE or its combination with sodium gluconate failed to provide flowability retention times which are commonly required by the ready-mix industry. Our study concludes that while such low carbon calcined mixed clay blended cements offer significant ecological advantages, they demand higher superplasticizer dosages which negatively affects their cost-effectiveness and at the same time poses significant technical challenges, particularly in ready-mix concrete applications. It should be mentioned that the problems pointed out here will be less severe for CMCs of lower metakaolin content.
Related References:
1. Andrew, R. M., Global CO2 emissions from cement production. Earth System Science Data 2018, 10 (1), 195-217.
2. Samarakoon, M. H.; Ranjith, P. G.; Rathnaweera, T. D.; Perera, M. S. A., Recent advances in alkaline cement binders: A review. Journal of Cleaner Production 2019, 227, 70-87.
3. Shi, C.; Qu, B.; Provis, J. L., Recent progress in low-carbon binders. Cement and Concrete Research 2019, 122, 227-250.
4. Scrivener, K.; Martirena, F.; Bishnoi, S.; Maity, S., Calcined clay limestone cements (LC3). Cement and Concrete Research 2018, 114, 49-56.
5. Siddique, R.; Klaus, J., Influence of metakaolin on the properties of mortar and concrete: A review. Applied Clay Science 2009, 43 (3-4), 392-400.
6. Fernandez, R.; Martirena, F.; Scrivener, K., The origin of the pozzolanic activity of calcined clay minerals: A comparison between kaolinite, illite and montmorillonite. Cement and Concrete Research 2011, 41 (1), 113-122.
7. Hollanders, S.; Adriaens, R.; Skibsted, J.; Cizer, Ö.; Elsen, J., Pozzolanic reactivity of pure calcined clays. Applied Clay Science 2016, 132-133, 552-560.
8. Tironi, A.; Trezza, M. A.; Scian, A. N.; Irassar, E. F., Potential use of Argentine kaolinitic clays as pozzolanic material. Applied Clay Science 2014, 101, 468-476.
9. Poon, C. S.; Kou, S. C.; Lam, L., Compressive strength, chloride diffusivity and pore structure of high performance metakaolin and silica fume concrete. Construction and Building Materials 2006, 20 (10), 858-865.
10. Batis, G.; Pantazopoulou, P.; Tsivilis, S.; Badogiannis, E., The effect of metakaolin on the corrosion behavior of cement mortars. Cement and Concrete Composites 2005, 27 (1), 125-130.
11. Brooks, J. J.; Megat Johari, M. A., Effect of metakaolin on creep and shrinkage of concrete. Cement and Concrete Composites 2001, 23 (6), 495-502.
12. Schmid, M.; Plank, J., Dispersing performance of different kinds of polycarboxylate (PCE) superplasticizers in cement blended with a calcined clay. Construction and Building Materials 2020, 258.
13. Li, R.; Lei, L.; Sui, T.; Plank, J., Effectiveness of PCE superplasticizers in calcined clay blended cements. Cement and Concrete Research 2021, 141, 106334.
14. Sposito, R.; Beuntner, N.; Thienel, K.-C., Characteristics of components in calcined clays and their influence on the efficiency of superplasticizers. Cement and Concrete Composites 2020, 110.
15. Plank, J.; Li, H.; Ilg, M.; Pickelmann, J.; Eisenreich, W.; Yao, Y.; Wang, Z., A microstructural analysis of isoprenol ether-based polycarboxylates and the impact of structural motifs on the dispersing effectiveness. Cement and Concrete Research 2016, 84, 20-29.
16. Plank, J.; Pöllmann, K.; Zouaoui, N.; Andres, P. R.; Schaefer, C., Synthesis and performance of methacrylic ester based polycarboxylate superplasticizers possessing hydroxy terminated poly(ethylene glycol) side chains. Cement and Concrete Research 2008, 38 (10), 1210-1216.
17. DIN EN 1015-3: 2007-5. In Methods of test for mortar for masonry –Part 3: Determination of consistence of fresh mortar (by flow table).
18. Lahalle, H.; Cau Dit Coumes, C.; Mercier, C.; Lambertin, D.; Cannes, C.; Delpech, S.; Gauffinet, S., Influence of the w/c ratio on the hydration process of a magnesium phosphate cement and on its retardation by boric acid. Cement and Concrete Research 2018, 109, 159-174.
19. Gmür, R.; Thienel, K.-C.; Beuntner, N., Influence of aging conditions upon the properties of calcined clay and its performance as supplementary cementitious material. Cement and Concrete Composites 2016, 72, 114-124.
20. Liu, X.; Wang, Z. M.; Li, H. Q.; Li, T., Mechanism and Application Performance of Slow-Release Polycarboxylate Superplasticizer. Advanced Materials Research 2012, 560, 574-579.
21. Cheung, J.; Jeknavorian, A.; Roberts, L.; Silva, D., Impact of admixtures on the hydration kinetics of Portland cement. Cement and Concrete Research 2011, 41 (12), 1289-1309.
22. Lv, X.; Li, J.; Lu, C.; Liu, Z.; Tan, Y.; Liu, C.; Li, B.; Wang, R., The Effect of Sodium Gluconate on Pastes’ Performance and Hydration Behavior of Ordinary Portland Cement. Advances in Materials Science and Engineering 2020, 2020, 9231504.
23. Ma, S.; Li, W.; Zhang, S.; Ge, D.; Yu, J.; Shen, X., Influence of sodium gluconate on the performance and hydration of Portland cement. Construction and Building Materials 2015, 91, 138-144.