This document is a Design Guide for the use of sandstone quarry sand (SQS) in South Wales. It is aimed at clients, contractors and specifiers who may wish to use the material and planners who have to assess applications involving the use of the material. Sandstone quarry sand is produced by the crushing and screening of the Pennant Sandstone at five quarries in South Wales. The crushed rock is valuable as an aggregate with excellent skid resistance properties, for use in the surface course of roads. Production of this aggregate however often leads to the generation of large amounts of fine material, known as sandstone quarry sand. The material is also referred to locally as sandstone dust and gritstone dust. The material is very well graded from a maximum grain size slightly larger than 3.5 mm to a clay fraction, with around 15-20% of the material smaller than 75 mu m, know as 'filler' or 'fines'. It is very consistent in grading and other properties. Exact levels of production are difficult to estimate, but it is likely that somewhere in the order of 0.9 million tonnes of SQS are produced in South Wales annually. The material is a charcoal grey colour and its well graded nature allows for good particle interlock and correspondingly good compaction. The potential for the fines to absorb water however is a significant issue with the material, as whilst the material exhibits excellent strength at optimum moisture content (OMC), the strength decreases dramatically when wet of optimum. However, it can be mixed with cement to form a versatile material for earthworks applications, or with compost to form a manufactured topsoil. This document aims to provide the reader with technical information on the material, to highlight applications that have been or are currently in use, and to disseminate the new applications that have been trialled as part of this study. A summary of the main applications is given in the following table. The aim is to encourage greater use of this valuable and versatile material. Use of this material can reduce the demand for land won or marine dredged sand and gravel, thus preserving valuable natural resources. It also ensures that the material is being used constructively, rather than accumulating in stockpiles in quarries or being used for low-value applications. Use of the material, where appropriate, will therefore contribute to sustainable development and should be encouraged. This Design Guide describes applications for which the material is suitable in South Wales. However, similar sandstone in other parts of the UK and elsewhere are also quarried for high skid resistance aggregates, resulting in the production of similar sandstone quarry sand. Many of the applications described may also be suitable in these other areas.

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