Enhancement of Workability of Cement-Poor Concrete by Optimizing Paste Content

Mohammed Hatem Mohammed^1,2*, Nadhir Al-Ansari¹, Sven Knutsson¹

¹Deparment of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå,Sweden.
²Department of Civil Engineering, University of Mosul, Mosul, Iraq.

DOI: 10.4236/eng.2014.613080                

Abstract

This study describes the performance of concrete in fresh state, intended for sealing deep bore-holes in the host rock of radioactive repositories. Set of different paste volumes, combinations of water-to-powder ratios and fine aggregate contents have been performed within the frame of this study. The main objective was to search for tendencies, logical connections and phenomena that occur for different combination of materials regarding the fluidity and segregation and mainly the effect from the (paste) or fine aggregate content. It shall be pointed out that this investigation is a suggestion on how concrete can be optimized using two simple test methods based on changing the paste content. The results highlighted the importance of having sufficient amounts of filler and cement paste for separate and carry larger particles, which gives the concrete good workability and fluidity at casting. It was concluded that the slump behaviors can be optimized based on the adjustments of the superplastisizer dosage.

Keywords

Concrete, Paste Content, Workability, Talc, Void Volume

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Pusch, R., Ramqvist, G., Bockgard, N. and Ekman, L. (2011) Sealing of Investigation Boreholes, Phase 4. Final Report SKB, Swedish Nuclear Fuel and Waste Management Co., Stockholm.
[2]	Pusch, R., Warr, L., Grathoff, G., Pour-bakhtiar, A., Knutsson, S. and Ramqvist, G. (2013) A Study on Cement-Poor Concrete with Talc for Borehole Sealing in Rock Hosting Radioactive Waste. Comunicacoes Geológicas, 5, 251-267.
[3]	Mohammed, M.H., Pusch, R., Al-Ansari, N., Knutsson, S., Jonasson, J.-E., Emborg, M. and Pourbakhtiar, A. (2013) Proportioning of Cement-Based Grout for Sealing Fractured Rock-Use of Packing Models. Engineering, 5, 765-774. http://dx.doi.org/10.4236/eng.2013.510092
[4]	Pourbakhtiar, A. (2012) Pilot Study of Method for Constructing Concrete Seals and Fracture Grouts in Deep Boreholes and Cementitious Backfills in Tunnels, Drifts and Shafts in Crystalline Rock. M.Sc. Thesis, Lulea University of Technology, Lulea.
[5]	Mohammed, M.H., Pusch, R., Al-Ansari, N., Knutsson, S., Emborg, M., Nilsson, M. and Pourbakhtiar, A. (2013) Talc-Based Concrete for Sealing Borehole Optimized by Using Particle Packing Theory. Journal of Civil Engineering and Architecture, 7, 440-455.
[6]	Pusch, R., Warr, L., Grathoff, G., Pourbakhtiar, A., Knutsson, S. and Mohammed, M.H. (2013) A Talc-Based Cement-Poor Concrete for Sealing Boreholes in Rock. Engineering, 5, 251-267. http://dx.doi.org/10.4236/eng.2013.53036
[7]	Kristoffer, N. (2005) Packing Theory for Crushed Aggregates in Concrete. Master Thesis, ETSEIB, Betongindustri AB, Lulea University of Technology, Lulea.
[8]	Mohammed, M.H., Pusch, R., Al-Ansari, N. and Knutsson S. (2012) Optimization of Concrete by Minimizing Void Volume in Aggregate Mixture System. Journal of Advanced Science and Engineering Research, 2, 208-222.
[9]	Utsi, S. (2008) Performance Based Concrete Mix-Design Aggregate and Micro Mortar Optimization Applied on Self-Compacting Concrete Containing Fly Ash. Ph.D. Thesis, Lulea University of Technology, Lulea.
[10]	Kennedy, C.T. (1940) The Design of Concrete Mixes. Proceedings of the American Concrete Institute, 36, 373-400.