Design of the flexible highway pavements by a computerized Aashto method

Abstract

ABSTRACT Although it may vary form... to country, highway construction investments constitute a high portion in rural transportation investments and expenditures. Especially, construction of the freeways may have even important negative impacts on the country's budget. Today, the construction cost of the pavement of a rural highway represents about 60% of the total cost of the construction in Turkey. Hence, a very careful and realistic design of the pavement is indispensable for satisfactory performance as well as economical solutions. At the beginning of a highway project, the priority for the design engineer is to take into consideration and to assure the required strength and load carrying capacity of the highway. In fact, there will always be different solutions or alternatives which may give satisfactory results, but only one of them will be the most economical solution. For important roads, sometimes an increase of 1 cm in pavement thickness, or the use of one material instead of another may have an important effect on the total cost. Hence precision and trial of the different alternatives may lead to more economical solutions. In this study, a computer aid design method based on AASHTO Guide procedures offers this opportunity to designer. The computer program presented in the study facilitates to obtain precise results and to test different data combinations. First, AASHTO Method of design, revised again in 1986, is introduced and then above mention computer program developed for flexible highway pavements is presented in detail. Computer program developed by the author minimized the assumptions thereby reducing technical and especially human errors. The use of the program shortens also the time for pavement design m