Research Home  Pavements Home 
REPORT 
This report is an archived publication and may contain dated technical, contact, and link information 

Publication Number:
FHWAHRT12030
Date: August 2012 
PDF Version (4.44 MB)
PDF files can be viewed with the Acrobat® Reader®
This chapter discusses the statistical analyses performed to develop the predictive models and the sensitivity analyses used to validate the models. All statistical analyses were performed using the SAS^{®} software program.
After data assembly was completed, predictive relationships for the parameters identified in table 6 through table 8 were considered for statistical analyses. The following approaches/ options were considered for developing the various models:
Data were formulated in three distinct types depending on the nature and extent of data available for each parameter and the intended use of the predicted variable. Within each type, different model forms can be adopted depending on the relationship the dependent parameter holds with the independent variables. The three primary data formulation types adopted are data formulation types 1 through 3 and are discussed in the following sections.
Table 13 to table 15 provide summaries of the model types evaluated for developing predictive relationships for PCC, stabilized, and unbound materials, respectively.
Material Property 
Primary Model 
Secondary Model 

Model Variables 
Model Type 
Model Variables 
Model Type 

Compressive strength 
Aggregate type, cement content, air content, w/c ratio, unit weight, admixtures, and SCMs 
1 
N/A 
N/A 
Elastic modulus 
Aggregate type, cement content, air content, w/c ratio, unit weight, admixtures, and SCMs 
1 
Compressive strength/ flexural strength 
1 
Flexural strength 
Aggregate type, cement content, air content, w/c ratio, unit weight, admixtures, and SCMs 
1 
Compressive strength 
1 
Indirect tensile strength (CRCP only) 
Compressive strength/flexural strength 
1 
N/A 
N/A 
CTE 
Aggregate type, aggregate volume, cement type, paste volume, and w/c ratio 
1 
Aggregate type 
2 
Erosion in CRCP design 
Base type, index properties and strength of base, and climate (precipitation) 
3 
N/A 
N/A 
EI—JPCP 
Base type, base properties, and climate (precipitation) 
3 
N/A 
N/A 
deltaT 
Base type, construction time, PCC index properties, and climatic variables 
3 
N/A 
N/A 
N/A = Not applicable.
Material Type* 
Material Property 
Constant or Time Dependent 
Independent Variables 
Model Type Evaluated 
Lean concrete and cementtreated aggregate 
Elastic modulus 
Constant 
Compressive strength 
1 
*All other material types have been excluded from this table, as the database provides data for LCB elastic modulus only.
Material Property 
Independent Variables 
Model Type 
Resilient modulus determined using the following two options: · Regression coefficients k_{1}, k_{2}, and k_{3} for the generalized constitutive model that defines resilient modulus as a function of stress state and regressed from lab resilient modulus tests · Determine the average design resilient modulus for the expected inplace stress state from laboratory resilient modulus tests 
Soil type, Atterberg limits, maximum dry density, optimum moisture content, gradation, and P_{200} 
1; after grouping data for coarsegrained and finegrained soils 
Topics: research, infrastructure, pavements and materials Keywords: research, infrastructure, pavements and materials, Pavements, LTPP, material properties, MEPDG, prediction model, Index properties TRT Terms: research, facilities, transportation, highway facilities, roads, parts of roads, pavements Updated: 10/26/2012
