Abstract
Abstract For highway construction or any superstructure, on dune sand, designers and construction teams must ensure that the foundation soil is stable enough to provide support for the applied loads. Sand dunes are stretched across Libyan deserts that make road construction a challenge because of the poor soil base. Replacement of such a weak soil is very expensive and not economically feasible, and, in many cases, there is no alternative soil nearby. This study used two different mix designs aimed at stabilizing the existing base course using a mix of dune sand and manufactured sand with a small percentage of Portland cement. Compaction, unconfined compressive strength and California bearing ratio tests were conducted on the treated sample with a varying cement proportion of 0%, 3%, 5% and 7% by weight. The first tests were done with a mix of 50% dune sand and 50% crushed sand that is shown to have excellent results. For a more economic design, this study also included testing of another mix design with 70% dune sand and 30% crushed sand; laboratory results show this 70%/30% mixture was appropriate to use as a base-treated material for road construction material. This mix resulted in overall superior performance. Its use will reduce the cost of road construction by saving materials and time, and it will also have lower environmental impacts in desert areas. This study has shown that the stabilization of weak material (desert sand) by using cement improves the strength characteristics of the treated soil.
Highlights
AND BACKGROUNDIn the southern region of Libya, the presence of abundant silica sand can be used as a local material in the construction of roads
Soils with >2% organic materials do not respond well to stabilization with cement due to the hydration effects introduced by the organic materials; this hydration may adversely affect the strength of the resulting soil [4]
The results of the mixture 50%/50%, natural and manufactured sands using different percentages of Portland cement, of 0%, 3%, 5%, 7% are illustrated in Fig. 6; the values of California bearing ratio (CBR) at the penetration of 2.5 mm for this mixture are 51.59%, 53.70%, 58.86%, and 59.19 %, respectively
Summary
In the southern region of Libya, the presence of abundant silica sand can be used as a local material in the construction of roads. This will help in preserving regional resources and avoids excessive pollution, helping vilify the impact on the environment due to transported materials. When the available soil is very weak, the stabilization process of soil depends on increasing the engineering characteristic of the soil and making it stable This process reduces the compressibility and permeability of the targeted mass of the soil, thereby increasing its strength, bearing capacity, durability and to reduce the cost of construction by using the local available materials [1, 2]. The OMC and the maximum specific gravity of dry soil vary with the amount of cement kiln dust [6]
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