FUNDAMENTAL CHARACTERISTICS FOR GROUND-RESISTANCE REDUCING MATERIAL USING WATER-ABSORBENT POLYMER

As the number of communication facilities increases, the number of gro unding points needed for the facilities increases. In the high ground- resistance areas with soils composed of volcanic ash or sand, it is di fficult to achieve the specified ground resistance and, hence, a groun d resistance-reducing material must be used. This paper proposes a met hod to reduce ground resistance using water-absorbent material. Also, a method is described for measuring ground resistance using a box-type metal container, where the influences from the walls and the bottom o f the metal container are taken into account. The properties of the gr ound resistance-reducing material based on the water-absorbent materia l which was solidified by using epoxy resin has been investigated to f ind the condition where the ground resistance was lower than when a gr ounding electrode was used and the compressive strength of the materia l was higher than that of bentonite. As a result, it was found that, w hen the water-absorbing ratio was 1:2, the ratio of the weight of the water-absorbent material to that of epoxy resin should be between 0.3 and 1.7. It was found also that this ground-reducing material was as e ffective as a grounding electrode with respect to the buried depth and earth conductivity and that the ground resistance decreased exponenti ally with a buried radius (alpha r(-0.37) 37).