Validity of sand dunes sediments as a fine aggregates for roads works: a case study on sand dunes sediments, Al-Nasiriya city, Southern Iraq

In light of the development and urban growth of the city of Al-Nasiriya, the road construction sector consumes the largest amount of aggregates. The research aims to study suitability of the sediments of the sand dunes extending on one side of the international road between Nasiriya – Baghdad near the check point of Fadak as fine aggregate used for the purposes of roads construction. The results of the geotechnical evaluation of physical properties showed that the grain size analysis of the fine aggregate did not meet the requirements of the Iraqi specification and according to these results, the aggregate needs to modify. Based on liquid limits and plasticity indices and according to Iraqi specification the deposits are suitable for using as sub-grade course materials and to construct the shoulders of the road but not suitable for using as sub-base course materials. While the results of chemical tests indicate that incompatibility of the rates of organic matters and calcium carbonates with Iraqi specification. On the other hand, the chemical analysis of the sediments showed that the rates of the chlorides, sulfates, gypsum, total soluble salts and pH they were within acceptable limits of standard specifications. The mineral components of the soils were characterized by clay minerals (kaolinite and montmorillonite) and non-clay minerals (quartz, feldspar, and calcite).