Bitumen Concrete Mix Design Using Cement and Phosphogypsum as Filler Materials

Fillers play an important role in engineering properties of bituminous paving mixes. Conventionally stone dust, cement and lime are used as fillers. An attempt has been made in this investigation to assess the influence of non-conventional and cheap fillers such as phosphogypsum (which is a waste product generated for phosphoric acid industries in large quantities discussed later) in combination with cement in asphalt paving mixes. It has been observed as a result of this study that asphalt mixes with these non-conventional fillers result in satisfactory Marshall Properties though requiring a bit higher bitumen content, thus substantiating the need for its use. The fillers used in this investigation are likely to solve the problem of solid waste disposal of the environment to a very large extent. In this study we have worked out the optimum percentage of cement and phosphogypsum to be mixed in bitumen which gives best results in Marshall Stability Test. The combination of both optimum values are then taken to prepare the Asphalt mix for paving flexible pavements. The various results obtained live upto the expectations and are tabulated later on.