Road condition surveys

Question 1

why do we need to assess pavement conditions

Answer 1

identify sites for treatment
prioritize sites for treatment
predict future conditions
allocate resource appropriately

Question 2

describe environmental and traffic factors for causing pavement deterioiration

Answer 2

environment : water and temperature

Traffic : axle loads, load configuration, edge fatigue, commercial vehicles

Question 3

Describe the usage of survey data:

Answer 3

structural conditions; protecting structural integrity of the existing pavement
safety condition; providing surfaces with adequate skid resistance
functional conditions; provide adequate ride quality

Question 4

Describe the 4 network level survey types

Answer 4

visual inspections : taken on foot or vehicle, assess broad range of defects, influenced by lighting,subjectivity

Structural survey ; assess structural capacity of pavements to carry current and future traffic, conducted with FWD or traffic speed deflectometer, required construction data and loading.

Skid resistance survey : function of road and tyre, provides insight into providing adequate skid resistance, useful as each site is different, thus, skid resistance is low in wet conditions

High speed surface conditions surveys; uses road assessment vehicles, operates at traffic speed, collects surface and geometric data, delivers surface conditions assessment

Question 5

Why is traffic management useful

Answer 5

sign control or stop/go for single carriageways
increases survey costs,
creates delay
surveying done off peak

Question 6

What are some useful outputs from the deflectograph

Answer 6

residual life of the pavement, where maintenance is required; the required thickness of the overlay to achieve the design objectives, identify long life pavements, priorities schemes

Question 7

describe the traffic speed deflectometer

Answer 7

doppler laser vertical velocity under the back axle

strength of road indicated by how quickly the road deflects.

Question 8

Describe the fwd

Answer 8

records deflection output bowls, enables assessment of the pavement layer, static operation so requires traffic management

Question 9

What are some typical tyre properties

Answer 9

dimension, rubber resiliance, tread pattern and depth, pressure and stiffness

Question 10

What are the differences between micro and macro texutre

Answer 10

micro = small scale texture of the pavement aggregate. Controls the contact between the tire rubber and the pavement surface.

Macro = large scale texture of the pavement as a whole due to the aggregate particle arrangement. Controls the escape of the water from under the tire; hence the loss of skid resistance with increased speed

Question 11

What are some parameters collected by a RAV

Answer 11

rutt depth, road roughness, macotexture, alignment, edge conditions, cracking

Question 12

what is the importance of measuring roughness

Answer 12

correlates with user perception of the road conditions
aligned to VOC
predictor of local defects
indication of structural weakness
change of roughness over time is a good measure of deterioration

Question 13

Describe texture depth

Answer 13

provide skid resistance,affects road safety, poor condition may not be apparent

Question 14

Describe edge conditioning

Answer 14

affects serviceability, affects road safety, indicates other failures

Question 15

what are some uses of high speed data

Answer 15

preperation of maintenance programmes, deterioriation modelling, financial modelling, life-cycle planning, identify risky areas
policy developement
highway asset valuation

Question 16

Outcomes of predicting deterioration

Answer 16

better idenfitication of preventative treatment programes
better understanding of the lifecycle of particular materials
better prediction of maintenance funding
better resource deployment
break reactive maintenance.