Solving the Optimization Model A careful study of the model shows that the presence of some terms such as obtained aashto from the multiplication of two unknown decision variables converts the optimization model to a nonlinear optimization model.

Figure 5: Optimal design thickness of asphalt concrete for major rural roads.

Design charts confirm that in the current situation (material aashto prices in 2015 application of asphalt treated pavement aashto layer in pavement structure is not cost effective.Guide basic design equation for flexible pavements. .ConsiderConsider the following: is construction cost of one square meter of pavement; is thickness of asphalt concrete layer (cm is thickness of asphalt treated base layer (cm is thickness of cement design treated base layer (cm is thickness of granular base layer (cm.After developing the optimization model, the optimum thickness of pavement layers for secondary rural roads, major rural roads, and freeways was determined based on the recommended prices in Basic Price List for Road, Runway pavement and Railway of Iran in 2015 and several charts were developed.They showed that pavements should be aashto designed for higher terminal serviceability index values than currently recommended.They developed pavement design charts as an design illustrative example to explain how the proposed methodology can be considered as an improvement over the deterministic design.(REK) tonasa XPT 35 semen MW tonasa cfpp Doc.The equation compares this to default values.2 for the immediately-after-construction value and.5 for end-of-life (terminal serviceability). .Also it was shown that, with increasing the strength of subgrade soil, the subbase layer may be removed from the optimum structure of pavement.In fact, four layers including asphalt treated base (ATB cement treated base (CTB granular base, and granular subbase can be considered or not considered in the pavement structure and by combination of these alternatives, total of 16 alternatives for structural configuration of pavement is achieved.Proposed model did not consider the treated base layers in pavement structure. And designed CBR needed for Roadbed is manual 20 and based on recommended value range of shadowhunters k value then taken modulus of subgrade around 200 psi/in.4 subbase based on aashto Design guide for design of pavement structure 1993, clause.6.2 since Total esal is 228,111.98.

End-of-life (called terminal serviceability.5.0 depending upon road use (e.g., interstate highway, urban arterial, residential) Subgrade support. .

Optimal Design of Flexible Pavements Based on ihap Code 234 Considering a six-layer pavement system as shown in Figure 1, the integer programming model to find the optimum structural configuration as well as optimum thickness of each corse layer can be written as follows.

According to Figure 1, if an asphalt treated base layer is used in the pavement structure, application of an additional tack coating becomes necessary; presence of term in the objective function reflects the additional cost in this case.When using the 1993 aashto, guide empirical equation or any other empirical equation, it is extremely important to know the equations limitations and basic assumptions. .The reliability of the pavement design-performance process is the probability that a pavement section designed using the process will perform satisfactorily over the traffic and environmental conditions for the design period (aashto, radio 1993 1 ). .Because of the peril associated with its use, often times the drainage coefficient is neglected (i.e., set as.0).Concrete Pavement Design, Construction, and Performance.English.820.000 Ergebnisse, datum, sprache, region m, the aashto Guide for Design of Pavement Structures (aashto, 1993) is the primary document used to design new and rehabilitated italiano highway pavements.If they are reasonably close (say within 5 percent) use the assumed.See more.gov.gov/./infrastructure/ pavements /ltpp/97091/97091.pdf PDF Datei, lTPP General, pavement, study Sites (fhwa-RD-97-086 and.The equations are based on a See more on pavementinteractive.For developing design charts, the resilient modulus of subgrade soil was assumed between 2 kg/cm2 with increments of 100 kg/cm2.However, due to the need for equipped labs and because extensive research is still vice needed for the use of mechanistic-empirical method, only empirical methods are used for pavement design in many countries.Otherwise, it is quite easy to use an equation with conditions and materials for which it was never intended. .Yield Strength ( Min.Rouphail proposed a mixed-integer programming model to identify the number, type, and thicknesses of paving materials required to meet the structural strength requirements of the pavement system at a minimum initial cost.