EVALUATION METHODS OF ROAD SURFACE PERFORMANCE IN JAPAN

EVALUATION METHODS OF ROAD SURFACE PERFORMANCE IN JAPAN

Kazuhiro WATANABEKazuhiro WATANABEPublic Works Research Institute, JapanPublic Works Research Institute, Japan

Kazuyuki KUBOKazuyuki KUBOPublic Works Research Institute, JapanPublic Works Research Institute, Japan

Masaru TERADAMasaru TERADAPublic Works Research Institute, JapanPublic Works Research Institute, Japan

Contents


1 INTRODUCTION

2 OBJECTIVE

3 SKID RESISTANCE

(1)Background(DF Tester)

(2)Relationship with braking force coefficient determined

using Friction Measurement Vehicle

(3)Investigation of the limits of using rubber pieces

(4)Investigation of the amount of water be sprayed

4 WATER PERMEABILITY

(1)Background

(2)Investigation on the inside diameter of the valve

(3)Investigation on the watertightness of water sealers

5 CONCLUSION


1.INTRODUCTION

1 Introduction The design guides for pavement were revised in 2001 in Japan

Specification-based StandardsSpecification-based Standards

Performance-based StandardsPerformance-based Standards

　 The road administrators specify the materials and structures of pavement.　 The constructors produced and applied asphalt mixes that satisfied the regulations in the manual.

The road administrators require performance for road surface through identifying the functions and needs of the surface of the road. The constructors can select and use materials that meet the required performances.


1.INTRODUCTION

Background of this revise …The functions required for pavement have

become increasingly diverse as society has developed.

The new rules have the freedom of designing pavement and selecting materials, respond to diverse needs, and encourage further technological innovation.

Therefore, various performance evaluation methods are being investigated in Japan.

2 Objective


2.OBJECTIVE

In this presentation, skid resistance and water permeability will be picked up and investigated toward appropriate evaluation.

Skid resistance : great relation to safety for driving a vehicle

the relationship with braking force coefficient determined Friction Measurement Vehicle and rolling skid number (RSN) determined by Dynamic Friction Tester (DF Tester)

the limits of using rubber pieces of DF Tester

the amount of water to be sprayed of DF Tester

To investigate

Water permeability : road noise reduction, traffic safety by preventing water from splashing during rainfall

the influence of the inside diameter of the valve in testers.

the watertightness of water sealers between road surface and testers

To investigate


3.SKID RESISTNACE

3 Skid resistance (1) Background (DF Tester)In Japan, Skid resistance is measured using…

Friction Measurement VehicleSkid Resistance Tester Based on Rotating Disc (DF Tester)The British Pendulum Tester

The second one which was developed in Japan is easy to measure, and has been standardized as an ASTM standard.


3.SKID RESISTNACE

Concept of DF Tester

Measurement of rolling skid number (RSN)

(2) Relationship with braking force coefficient determined using Friction Measurement Vehicle


3.SKID RESISTNACE

Braking force coefficient and RSN

In any type of DF Tester, They have good correlation.


3.SKID RESISTNACE

Braking force coefficient and RSN at each speed

Within the range of V=40 to 60km/h, there was a close correlation.

V=20km/h V=40km/h

V=60km/h V=80km/h

(3) Investigation of the limits of using rubber pieces


3.SKID RESISTNACE

Changes in rubber piece thickness

These figures showed that it is adequate to express the limit of using rubber pieces not by the number of measurements but by the degree of abrasion.

Changes in RSN during repeated measurements

So, we investigated the relationship between the rubber thickness and RSN.


3.SKID RESISTNACE

Rubber thickness and RSN (All kinds of pave.)

These figures showed that rubber pieces should be recommended to be exchanged when they have abraded by 0.5mm.

Rubber thickness and RSN (dens graded pave.)

(4) Investigation of the amount of water be sprayed


3.SKID RESISTNACE

Water runoff and RSN (dense graded pave.)

ASTM does not prescribe the difference in water head for spraying water during measurements. ( It states that the flow should be kept at 3.6L/min when the tank for supplying water is 0.6m above the tester.)We investigated the relationship between the amount of water be sprayed and RSN.

Not great influence on RSN from 2.2 to 4.0 L/min

Should be investigated in advance to give a flow of 3.6L/min that ASTM said

　

Valve

Water sealer

(unit : mm)

support

Doughnut-shaped weight

Valve

Water sealer

(unit : mm)

support



4.WATER PERMEABILITY

4 Water permeability (1) BackgroundIn Japan, porous asphalt pavement is increasingly used mainly on major roads to reduce traffic noise and ensure traffic safety by preventing water from splashing during rainfall.

The current evaluation method involves measuring the amount of penetrated water by using an in-situ permeability tester like right side figure.

This figure shows care must be taken on the inside diameter of the valves to be used (the inside diameter of the valves 8 mm or larger).

　

1,200

1,300

1,400

1,500

1,600

1,700

500 550 600 650 700水　頭　（mm）

浸透

水量　（m

l/15sec）

：φ 6.8mm：φ 8mm：φ 10mm

Water head (mm)

Wat

er

perm

eab

ility

(m

L/1

5se

c)

1,200

1,300

1,400

1,500

1,600

1,700

500 550 600 650 700水　頭　（mm）

浸透

水量　（m

l/15sec）

：φ 6.8mm：φ 8mm：φ 10mm

Water head (mm)

Wat

er

perm

eab

ility

(m

L/1

5se

c)



(2) Investigation on the inside diameter of the valveThe inside diameters of the valves of the testers sold in Japan were found to be 6.8, 8 and 10 mm.So we investigated the influence by these difference.

　

Valve

Water sealer

(unit : mm)

support


Valve

Water sealer

(unit : mm)

support


　

Valve

Water sealer

(unit : mm)

support


Valve

Water sealer

(unit : mm)

support




(3) Investigation on the watertightness of water sealersVarious kinds of water sealer are used for permeability testers.Because the current evaluation method directly measures the amount of water that flows into pavement, differences in the watertightness of water sealers are likely to strongly affect permeability measurements.So we investigated the influence depends on water sealers.

This figure shows highly watertight materials such as putty need to be used to seal in order to correctly evaluate.

　

Wat

er p

erm

eabi

lity

(mL/

15se

c)

Rubber ring Silicon mat Putty appliedRubber ring(standard) + silicon mat (no rubber ring)

Ways to cut off waterto cut off water

Wat

er p

erm

eabi

lity

(mL/

15se

c)

Rubber ring Silicon mat Putty appliedRubber ring(standard) + silicon mat (no rubber ring)

Ways to cut off waterto cut off water


5.CONCLUSION

5 ConclusionThere was a close correlation between RSN determined by DF Tester and the measurement by Friction Measurement Vehicle, especially within the range of V=40 to 60km/h.The rubber pieces which installed on a rotary disk of DF Tester should be exchanged before they abraded by 0.5mm.The amount of water to be sprayed from 2.2 to 4.0L/min in testing didn’t have great influence on RSN.

<SKID RESISTANCE>

<WATER PERMEABILITY>If the diameter of the valves is 6.8mm that is smaller than the inside diameter of the connecting pipes (=8.0mm), it has great possibility to evaluate performance of water permeability unfairly.Highly watertight materials need to be used between road surface and tester in order to correctly evaluate the seepage of rainwater into pavement.


5.CONCLUSION

We will continue to study methods of evaluating various performance indices, aiming to establish methods that can correctly assess the performance requirements for pavement, encourage further innovations of pavement-related technologies, and improve the effects and efficiency of paving works.

[email protected]

Thank you for your kind attention.

Date post:	31-Dec-2015
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EVALUATION METHODS OF ROAD SURFACE PERFORMANCE IN JAPAN

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