DBPapers
DOI: 10.5593/sgem2017/62/S26.019

ENGINEERING PROPERTIES OF CONCRETE SUITABLE FOR CONSTRUCTING PHYSICAL BARRIERS IN RADIOACTIVE WASTE DISPOSAL FACILITIES

E. Vejmelkova, J. Kotatkova, P. Bezdicka, P. Konvalinka, R.Cerny
Tuesday 12 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-13-3 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 62, 147-154 pp, DOI: 10.5593/sgem2017/62/S26.019

ABSTRACT

Several concrete mixtures suitable for constructing engineered barriers in radioactive waste disposal facilities are designed and tested. The mix design is based on the utilization of a natural sorbent acting, at the same time, as supplementary cementitious material replacing a part of Portland cement and fine filler capable of radionuclide absorption and fixing. A representative set of engineering properties of the hardened concrete mixes is determined, including the pore size distribution, bulk density, matrix density, open porosity, compressive strength, water absorption coefficient, and apparent moisture diffusivity. Experimental results show that an appropriate dosage of the natural sorbent in the analyzed concrete is within the range of 30-50% of the mass of Portland cement. This level of Portland cement replacement makes possible to utilize effectively the pozzolanic properties of the sorbent and still preserve its necessary amount in the nonhydrated state. The mechanical properties of concrete are then satisfactory for the supposed load, the water-penetration protection ability is sufficient, and the microcrystalline structure of non-hydrated sorbent can provide a sufficient interior pore surface area for fixing the anticipated radionuclide dose.

Keywords: cement composites, radioactive waste disposal, engineering properties, pore size distribution