Compressive strength and thermal properties of sand–bentonite mixture

Abstract

Sand–bentonite mixtures are used in road embankments as a protective material for protecting underground high-voltage cables and utility pipelines supplying water and gas etc. The sand–bentonite mixtures provide benefits while laying high-voltage cables. The purpose of this study is to determine the proportions as well as mechanical and thermal properties of a dry-mixed sand–bentonite mixture and to investigate the suitability of such mixtures for installation around high-voltage underground power lines in road embankments. When selecting a sand–bentonite mixture, the following requirements must be ensured: the compressive strength must be greater than 0.5 MPa after 24 h; the thermal resistivity must be greater than 1.2 K m/W (thermal conductivity 0,833 W/(K m)); and the moisture content of the sand–bentonite mixture must be less than 13%. The following materials were used when selecting the bentonite mixture: bentonite, 0–4.0 mm fraction sand, cement (CEM I 42.5R), and water. In this study, six groups of samples were formed, in which the parts of concrete, sand, cement, and water were added in different proportions. The strength and thermal conductivity of the samples were analyzed. Studies about the use of bentonite around high-voltage cables have revealed the need for wet mixing of bentonite suspensions. The required thermal conductivity properties of the soil were not achieved by dry mixing. This method of mixing can be useful only in cases when the thermal conductivity of the mixed soil is not relevant, because the work can be continued after a day.

Experiment-Based Study of Heat Dissipation from the Power Cable in a Casing Pipe

“…It is widely used as a standard substrate strengthening material. The sand-bentonite mixture (cable bentonite) is commonly used to fill the space surrounding the cables inside casing pipes, in order to increase the ampacity of the cables and to stiffen the cable arrangement [19][20][21]. Bentonite swells when hydrated and retains water, thus ensuring that the voids created by the sand skeleton are filled [22].…”

Sand modification with a saponite clay suspension as a waste of the diamond mining industry

“…Проводились исследования по применению на свалках смесей бентонита с каменноугольной золой [13]. Используют ПБС и для изоляции каналов с высоковольтными кабелями [14].…”