Question

1. describe the methods for determining roadway condition

Answer 1

The methods of determining the roadway condition

There are three type of road for each the conditions of spectacular character is different. The different type of roads is rigid, flexible and overlay roads. Even though the serviceability and condition can check by users, equipment surveys will conduct to collect the results on slope, skid character, serviceability etc and then apply on equations. Different methods are using   to calculate the mathematical result of serviceability of roadway condition.

AASHO Serviceability equations

The original equations took into account cracking, patching, rut depth and slope variance. For rigid and flexible pavement, equations are different.

For rigid pavement, p=5.41-1.78(1+SV)-0.9(root of (C+P)

For flexible pavement, p=5.03-1.91 log (1+SV)-0.01(root of(C+P) - 1.38(RD)²

Where, SV – Slope variance

                C – Major cracking

                P – Bituminous patching

                RD – Average rut depth

Slope profilometer is used to measure the slope variance.

COMBINED EQUATIONS

The equations combined with available data in the present to the mathematical formula to fnd out the results. Using combined equations with equipment equations is to be recommended to predict the present serviceability of roadway conditions.

The road roughness equipment used in the determination is,

§ Bureau of Public Roads roughometer

§ AASHO slope profilometer

§ CHLOE Profilometer

§ Texas Texture Meter

§ Kentucky highway Department Accelerometer Device

§ University of Michigan truck profilometer

§ General motors’ corporation profilometer

Cracks, Faulting cracks and joints, patching, blow ups,rutting, bleeding and ravelling are some defect usually found in the pavements. Equipment survey has given the mathematical results of all conditions in the pavement.