Influence of Gum Acacia Karroo on Some Mechanical Properties of Cement Mortars and Concrete

Natural admixtures provide concrete with enhanced properties but their processing end up making them very expensive resulting in increase to cost of concrete. In this study the effect of Gum from Acacia Karroo (GAK) as set-retarding admixture in cement pastes was studied. The possibility of using GAK as water reducing admixture both in cement mortar concrete was also investigated. Cement pastes with different dosages of GAK were prepared to measure the setting time using different dosages. Compressive strength of cement mortars with 0.7, 0.8 and 0.9% weight of cement and w/c ratio of 0.5 were compared to those with water cement (w/c) ratio of 0.44 but same dosage of GAK. Concrete samples were prepared using higher dosages of GAK (1, 2 and 3% wt of cement) and a water bidder (w/b) of 0.61 were compared to those with the same GAK dosage but with reduced w/b ratio. There was increase in compressive strength of 9.3% at 28 days for cement mortar samples with 0.9% dosage of GAK and reduced w/c ratio.

Authors:

• Rose Mbugua
• Ramadhan Wanjala
• Julius Ndambuki

Keywords:

• Compressive strength
• Gum Acacia Karroo
• retarding admixture
• setting time
• water-reducing admixture.

References:

[1] J. Stark, “Recent advances in the field of cement hydration and
microstructure analysis,” Cement and Concrete Research, vol. 41, no. 7,
pp. 666–678, 2011.
[2] K. H. Khayat and A. Yahia, “Effect of welan gum-high-range water
reducer combinations on rheology of cement grout,” ACI Materials
Journal, vol. 94, no. 5, pp. 365–372, 1997.
[3] K. H. Khayat, “Viscosity-enhancing admixtures for cement- based
materials- an overview,” Cement and Concrete Composites, vol. 20, pp.
171–188, 1998.
[4] T. Kawai and T. Okada, “Effect of superplasticizer and
viscosity-increasing admixture on properties of lightweight aggregate
concrete,” ACI Special Publication, vol. 119, 1989.
[5] L. Ma, Q. Zhao, C. Yao, and M. Zhou, “Impact of welan gum on
tricalcium aluminate–gypsum hydration,” Materials Characterization,
vol. 64, pp. 88–95, 2012.
[6] M. Cappellari, A. Daubresse, and M. Chaouche, “Influence of
organic thickening admixtures on the rheological properties of
mortars: Relationship with water-retention,” Construction and Building
Materials, vol. 38, pp. 950–961, 2013.
[7] D. Verbeken, S. Dierckx, and K. Dewettinck, “Exudate gums:
occurrence, production, and applications,” Applied Microbiology and
Biotechnology, vol. 63, no. 1, pp. 10–21, 2003. [8] J. J. Coppen, “Gums, resins & latexes of plant origin. non-wood forest
products,” 1995.
[9] N. A. Ademoh and A. Abdullahi, “Determination of the physio-chemical
properties of nigerian acacia species for foundry sand binding
applications,” Research Journal of Applied Sciences, Engineering and
Technology, vol. 1, no. 3, pp. 107–111, 2009.
[10] S. Al-Assaf, G. O. Phillips, and P. A. Williams, “Studies on acacia
exudate gums: part ii. molecular weight comparison of the vulgares and
gummiferae series of acacia gums,” Food Hydrocolloids, vol. 19, pp.
661–667, 2005.
[11] V. S. Ramachandran, Concrete admixtures handbook: properties, science
and technology, 2nd ed. Ottawa, Canada: Noyes Publication, 1995, no.
ISBN0-8155-1373-9.
[12] R. Dyer, “Acacia karroo in southern africa,” Bothalia, vol. 10, no. 2, pp.
385–401, 1971.
[13] N. Abdeljaleel, A. Hassaballa, and A. R. E. Mohamed, “The use of gum
arabic liquid and modified liquid in concrete mixes,” Innovative Systems
Design and Engineering, vol. 3, no. 12, pp. 1–11, 2012.
[14] A. Jumadurdiyev, M. Hulusi Ozkul, A. R. Saglam, and N. Parlak, “The
utilization of beet molasses as a retarding and water-reducing admixture
for concrete,” Cement and concrete research, vol. 35, no. 5, pp. 874–882,
2005.
[15] B. Khan and B. Baradan, “The effect of sugar on setting-time of various
types of cements,” Science Vision, vol. 8, no. 1, 2002.
[16] S. Alsadey, “Effects of super plasticizing and retarding admixtures on
properties of concrete.”