الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The problem that frequently confronts a contractor as he plans to construct a project, it the election of the most suitable equipment.
As an investment, which he can expect to recover, with a profile during the useful life of the equipment? Contractor does not pay for construction equipment.
The equipment must pay for itself by earning for the contractor more money that costs. Unless – in advance- the unit of equipment will earns more than it costs, it should not be purchased.
Contractor can never afford to own all types or sizes of equipment that might be used for the kind of work he does. It may be possible to determine what kind and size of equipment seem most suitable for a given project, but this information alone is not necessarily the reason for purchasing the equipment.
The great tendency toward mechanization of construction requires a large capital investment to be employed in construction equipment, especially for heavy construction contractors where equipment cost represents 35% or more of the total project cost (14). Consequently, the contractors’ equipment policies greatly affect their project profitability.
They have also a great impact on the contractor’s ability to be competitive, in an economic sense, with other contractors.
There are many factors that affect the aging of the equipment.
These factors are, investment cost, loss in market value, maintenance and repair costs, overhaul cost, equipment revenue, and downtime.
Some of these factors change is progressive with the aging of the equipment where the change is retrogressively (15).