Ignition of waste paper sludge at elevated temperatures to produce electricity in power generation plants utilizing fluidized bed combustion generates paper sludge ash. Due to the high concentration of lime and gelignite in paper sludge ash, it is expected that it will play a vital role as a cementitious material. This paper investigates the use of paper sludge ash to improve the mechanical properties of the granular materials, which are suitable to subbase course for road and building constructions. Also, a comparison study with the use of Portland cement as an additive to granular materials has been covered. The mechanical properties were evaluated by conducting the California bearing ratio test for the two adopted methods. Moreover, the compressive strength of the samples using paper sludge ash and cement are investigated. In accordance to the California bearing ratio test, 4% paper sludge ash was indicated as the optimum ash content at which the California bearing ratio value increased by 173% and 111% in comparison with untreated material and 6% cement, respectively. On the other hand, and by means of the compressive strength, the granular materials with 4% paper sludge ash has compressive strength higher than those with 6% cement.
Ondova, M. Stevulova N., Palascakova L., Estokova A. The study of concrete properties prepared with a proportion of fly ash, Pollack Periodica, Vol. 9, No. Supplement 1, 2014, pp. 105‒115.
El Mir A., Nehme S. G. Effect of air entraining admixture on the properties of self-compacting concrete incorporating supplementary cementitious materials, Pollack Periodica, Vol. 12, No. Supplement 3, 2017, pp. 85‒98.
Sahu B. K. Improvement in California bearing ratio of various soils in Botswana by fly ash, International Ash Utilization Symposium, University of Kentucky, USA, 2001, Paper No. 90, pages 7.
Dutta R. K., Sarda V. K. CBR behavior of waste plastic strip-reinforced stone dust/fly ash overlying saturated clay, Turkish J. Eng. Env. Sci. Vol. 31, 2007, pp. 171‒182.
Rajak T. K., Pal S. K. CBR values of soil mixed with fly ash and lime, International Journal of Engineering Research & Technology, Vol. 4, No. 2, 2015, pp. 762‒768.
Jafer H. M., Atherton W., Ruddock F., Loffill E. The utilization of two types of fly ashes used as cement replacement in soft soil stabilization, World Academy of Science. Engineering and Technology, International Journal of Civil and Environmental Engineering, Vol. 10, No. 7, 2016, pp. 933‒936.
Pai R. R., Patel S. Effect of GGBS and lime on the strength characteristics of black cotton soil, in Thyagaraj T. (Ed.) Ground Improvement Techniques and Geosynthetics, Lecture Notes in Civil Engineering, Vol. 14. Springer, Singapore, 2016, Indian Geotechnical Conference, Madras, Chennai, India, 15-17 December 2016, pp. 319‒328.
AASHTO T90, Standard method of test for determining the plastic limit and plasticity index of soils, 2004.
BS 1377-3:2018, Methods of test for soils for civil engineering purposes, Chemical and electro-chemical tests, 2018.
AASHTO T-180, Standard method of test for moisture-density relations of soils using a 4.54-kg (10-lb) rammer and a 457-mm (18-in.) drop, 2004.
AASHTO T-193, Standard method of test for the California bearing ratio, 2004.