Preliminary studies on the utilisation of Berea Red Sands for sub-base and base construction

Abstract

Berea Red sands occur in abundance on the eastern seaboard of KwaZulu-Natal and Mozambique. The material is of Aeolian origin and is seldom used as base and sub-base material in the region, even on lightly trafficked roads. The main reasons for the material being discarded revolve around the supposed variability of the material and it being supposedly substandard. However recent studies, undertaken by the CSIR, have shown that although the material has certain limitations e.g. Grading Modulus (GM), it is the lack of knowledge about this material which is the main shortcoming. The paper presents preliminary findings of the investigations on the utilisation of Berea Red sands in the construction of sub-base and base layers in roadworks. The investigations and studies have shown that Berea Red Sands: Are no more variable than most sources of natural gravels obtained from borrow pits or construction cuttings. What has lead to some confusion is that all the "sandy material" along the east coast has been referred to as "Berea Reds" irrespective, of the colour of the sand, and can be economically modified/stabilised/physically changed to make them suitable for use as a sub-base and base layers for road works. In addition from cores, taken as part of the study, from roads constructed in three different areas, it is quite clear that the lime stabilised Berea Red material used in sub-base and base construction, is in a surprisingly good condition after a period of some 30-40 years (there have been authorities that have claimed that lime stabilisation is not of a permanent nature)