Dear Hossain, 

Here you have some examples: 

Article Correlation analysis between international roughness index (...

Article Estimating International Roughness Index from Pavement Distr...

Conference Paper Jyh-Dong Lin, Jyh-Tyng Yau, Liang-Hao Hsiao, (2002) “Correla...

Article International Roughness Index Prediction for Rigid Pavements...

Dear Hossein Mohammadi,

i am attached here a link. pl see this paper "Performance Models for Rural Roads"

http://irc.org.in/ENU/Documents/IH/IH%202014/FEB-2014.pdf

The answer for your question may be dependent on the type of pavement (rigid / flexible) and traffic (light / heavy). Are you applying this to some particular road?

i want to apply this for flexible pavement. 

also i'm going to use this for highway,arterial and collector roads.

Dear Hossein

I agree with Luis.

IRI represents surface defects whereas PCI is estimation of both surface and structural defects. Therefore it is hard to get a good relationship between IRI and PCI.

Dear Hossein,

pl check attachment that i send previous. ( "Performance Models for Rural Roads") The various models developed for flexible pavement.

All the best

Dear Hossein,

i send you link to interesting text which deals with correlation between IRI and PCI. /http://d92016.eos-intl.net/eLibSQL14_D92016_Documents/2014-03_IRI-PCI%20Final%20Report.pdf). Another interesting text is final report of COST354 action but it does not use PCI as a parameter with which you can estimate a condition of road.

All the best, Tanja

Dear Hossein,

The report that Tatjana sent is good. But, please note the comments made by Luis and Sinnappoo. The correlations will be very much dependent on the level of maintenance and rehabilitations. For example the IRI in the wheelpath picks up mainly the distresses such as corrugation, depression (short lengths), bumps and sags, potholes. But, not the low and moderate ravelling, bleeding, carackings (unless they are severe enough to contribute to roughness), etc, So, the correlations as commented by others can best be used as a rough estimate. Because, they depend on the class of the road, level of maintenance, environment, etc. that could be very different from a country to anither. Therefore, You can't use the ones from the Washington DC area to your locality of Zanjan.

Regards,

Dear Hossein

I agree with Dr. Tabatabaee and Sinnappoo

Several types of pavement condition indices can by adopted, these are:

PSR, PSI, MCI (JAPAN), IRI, SR (SURFACE RATING), SKID RESISTANCE, PQI AND PCI

The IRI is a standard roughness measurement in regarded to measurements acquired by road meters installed on cars or trailers. The IRI is a mathematical model used to a measured profile. The model simulates a quarter-car system (QCS), traveling at a constant speed of 80 km/hr. The IRI is calculated as the cumulative movement of the suspension of the QCS divided by the traveled distance.

From the above definition, its obvious that the IRI deal with the functional performance of pavement.

The PCI is a numerical index, ranging from 0 for a failed pavement to 100 for a pavement in perfect condition. PCI was developed by the U.S. Army Corps of Engineers. The PCI is an evaluation procedure that is determined in accordance with procedures contained in ASTM D 5340, Standard Test Method for Pavement Condition Index Survey. The procedure is used to provide a measurement of the condition of pavements taking into account the functional performance with implications of structural performance.

From the above, Its obvious that the PCI deals with both pavement structural performance and functional performance.

regards

TRB Paper#17-02203

Validation and Improvement of Pavement ME Flexible Pavement Roughness Prediction Model using Extended LTPP Database

96th Annual Meeting of the Transportation Research Board

Washington D.C., USA

January, 8-12, 2017

In Ontario, Canada MTO estimates PCI from DMI and IRI using this relationship.

Flexible Pavement: PCI  = (13.75) + (9xDMI) - (7.5xIRI)

Where,

PCI is the pavement condition index

DMI is the subjective distress manifestation index, theoretically ranging from 0 to

10, where 0 indicates the worst condition well 10 represents the excellent

condition

IRI is the international roughness index

More information can be found in the 2013 MTO Pavement Design and Rehabilitation Manual.

I agree with Amjad AlBayati

i agree with amjad Albayati.