transport and road research laboratory …the length of unreinforced pavement with narrow unsealed...

TRANSPORT and ROAD RESEARCH LABORATORY

Department of the Environment Department of Transport

SUPPLEMENTARY REPORT 682

THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M 180 (SANDTOFT TO TRENT SECTION)

by

J M Gregory FIHE

Any views expressed in this Report are not necessarily those of the Department of the Environment or of the Department of Transport

Construction and Maintenance Division Highways Department

Transport and Road Research Laboratory Crowthorne, Berkshire

1981 ISSN 0305-1315

Ownership of the Transport Research Laboratory was transferred from the Department of Transport to a subsidiary of the Transport Research Foundation on 1 st April 1996.

This report has been reproduced by permission of the Controller of HMSO. Extracts from the text may be reproduced, except for commercial purposes, provided the source is acknowledged.

Abstract

1.

2.

.

CONTENTS

Introduction

Construction

2.1 Earthworks

2.2 Sub-base

2.3 Separation membrane

2.4 Carriageway paving

2.4.1 Concrete

2.4.1.1 Mixing and transport

2.4.1.2 Control

2.4.2 Reinforcement

2.4.2.1 Laps

2.4.3 Joints

2.4.3.1 Expansion joints

2.4.3.2 Contraction joints

2.4.3.3 Wide-flange beam joints

2.4.3.4 Construction joints in CRCP

2.4.3.5 Longitudinal joints

2.4.3.6 Joints between concrete and flexible construction

2.4.4 Surface texture

2.5 Hardshoulder

2.5.1 Transverse joints

Testing and control

3.1 Sub-base

3.1.1 Granular sub-base material Type 1

3.1.2 Cement-bound granular material

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3.2 Concrete carriageway slabs

3.2.1 Plastic concrete

3.2.2 Hardened concrete

3.2.2.1 Cores

3.2.3 Surface characteristics

3.2.3.1 Surface regularity

3.2.3.2 Surface texture

3.3 Concrete slabs in hardshoulders

3.3.1 Plastic concrete

3.3.2 Hardened concrete


3.3.3.1 Surface regularity

3.3.3.2 Surface texture

Remedial actions

Comments on construction

5.1 Tolerances

5.1.1

5.1.2

5.1.3

5.1.4

Slab thickness

Reinforcement position

Reinforcement ripple

Omission of separation membrane

Costs

Performance

Acknowledgements

References

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(C} CROWN COPYRIGHT 1981 Extracts from the text may be reproduced, except for

commercial purposes, provided the source is acknowledged

THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M180 (SANDTOFT TO TRENT SECTION)

ABSTRACT

This report describes the construction of the experimental concrete carriageways on the Sandtoft to Trent section of M180; the design of this experiment has been reported in SR 653.

Construction of the 11.2m wide concrete carriageways was carried out in one operation by a slip-form paver. The maximum length laid in one day was 1132m and an average daily output of 502m was achieved. The hardshoulder was also paved in concrete by a small slip-form paver which formed the integral drainage channel.

The results of tests on the plastic and the hardened concrete are reported, together with summaries of the results of tests on the finished surfaces.

1. INTRODUCTION

The major purpose of the experiment is the investigation of the design, construction, cost and performance of

continuously reinforced concrete pavements (CRCP). Variables for other purposes are also included in the experi-

mental carriageways; the design of the experiment has been described in Supplementary Report 6531. The layout

of the experiment is shown in Figure 1.

2. CONSTRUCTION

The contractor for all the works connected with the contract was Sir Alfred McAlpine and Son (Northern) Limited;

work on the 24 month contract commenced in November 1976. The contract length was extended by four months;

the majority of the extension granted was as a result of exceptionally adverse weather conditions early in the

contract period.

2.1 Earthworks

Nearly all the earthworks consisted of shallow embankments; these were constructed of imported marl fill

from nearby disused brickworks.

Settlements of up to one metre are predicted to occur at the eastern end of the section (east o f chainage

10157+00), where there is underlying peat up to 6m thick. The CRCP over this area have been strengthened by

additional transverse reinforcement (16 mm diameter bars of deformed steel, placed at 500 m m centres). Settle-

ments are being frequently monitored and the performance of the CRCP over this length will be watched with

particular interest.

2.2 Sub-base

The sub-base under all sections of jointed pavement, including transition bays, was 180 mm thick granular

material Type 1 ; it complied with the requirements of the Department of the Environment Specification for road

and bridge works 2. The crushed limestone aggregate used was spread by graders and compacted by vibratory

rollers.

Under the CRCP sections the sub-base consisted of 150 mm of cement-bound granular material laid on a

similar Type 1 granular sub-base material of such thickness that the total construction depth was 460 mm. The

cement-bound granular material was mostly made with a 37.5 mm maximum size slag aggregate with cement

contents varying from 4 to 7 per cent. It was mixed in the 7.5 m 3 capacity tilting drum mixer used to produce the

pavement quality concrete.and laid, by a rubber-tyred bituminous-materials paver, in widths up to 5.3m; compaction

was by a combination of vibratory and smooth-wheeled rollers. Small areas were infdled with cement-bound

granular material using the crushed limestone granular Type 1 material as aggregate. After rolling, the sub-base

was cured with a bituminous emulsion spray.

2.3 Separation membrane

A separation membrane, used beneath all the sections except the CRCP and the transition sections and half

the length of unreinforced pavement with narrow unsealed joint grooves, consisted of a 65 pan thick polythene

sheering laid on the sub-base.

2.4 Carriageway paving

The construction o f each 11.2m concrete carriageway was carried out in one operation using the Guntert

and Zimmerman slip-form paver shown in Hate 1. Control wires, positioned on either side of the paver outside its

crawler tracks were used for level control; one of these wires was also used for control of alignment. The guide

wires were supported on steel pins spaced 6m apar t . Following the paver were a transverse joint groove-forming

machine, a transverse joint finisher, and a combined brush-texturing and curing spray machine all mounted on

rubber-tyred wheels and guided f rom the control wires. Box-outs for road studs were inserted by hand after the

transverse joint finisher had passed and were removed after the curing spray was applied.

On both carriageways paving commenced at the western end of the site. On the Westbound carriageway,

a 6m long transition slab at the western end o f the 210 m m thick CRCP section with fabric reinforcement was

omit ted in order to permit access for lorries transporting the concrete from the mixing plant; this slab was

subsequently hand laid. Paving started on 21 June 1978 with the laying of the trial lengths (in unreinforced

construction) on the Westbound carriageway. This carriageway was completed on 13 July 1978. On the Eastbound

carriageway, paving commenced on 17 July 1978 and was completed on 5 August 1978. The maximum length

laid in one day was 1132m and the average daily output was 502m.

2.4.1 Concrete: Three different concrete mixes were used during the construction of the carriageways; details

are given in Table 1.

TABLE 1

Concrete mix proportions

Material

Cement

Sand

Coarse Aggregate

Water

Air-entraining agent

Type

Ordinary Portland

Quartzitic (Zone 3)

Limestone 1 0 - 5 mm

Limestone 2 0 - 1 0 mm

Weight (kg) per m 3

Mix l Mix2

280 280

704 710

370 379

776 794

154 154

Mix 3

315

760

363

688

173

Varied between 80 and 120 cc per 50 kg of cement

Mix 1 was used for the period 21 June to 2 July 1978. Mix 2 was used for the period 3 July to 15 September 1978. Mix 3 was a pumped mix.

The pumped mix was used only at two locations on each carriageway where, because of the central bridge

piers, it was not possible to take the side-feeder through the bridges while attached to the slip-form paver.

Accelerated wear testing, as required by Clause 1001 of the Specification 2, showed that the limestone

aggregate proposed by the contractor was acceptable. The cement content used was the minimum allowed in the

Specification (280 kg/m3), a trend that has been observed on most concrete paving contracts where the indirect

tensile strength test has been used as the acceptance criterion.

2.4.1.1 Mixing and transport: Concrete mixing was carried out at a central batching and mixing plant set up

near the western end of the contract; the mixer was of the tilting-drum type with a capacity of 7.5m 3. The mixed

concrete was transported in 4-axle non-tipping ejector trucks with a 7.5m 3 capacity to match the batch size;

most loads were 7m 3. The trucks were fitted with hydraulically operated bulkheads and tailgates which enabled

rapid controlled discharge into the side-feeder attached to the slip-form paver. The concrete was only covered

during transit from the mixer to the paving site when weather conditions warranted this.

2.4.1.2 Control: Workability was controlled by means of the Slump Test carried out by the contractor at the

mixing plant and by the client at the laying site; the contractor also used a wat tmeter on the mixer as a control aid.

Similarly, air content measurements were made at both mixing and laying sites. For compliance with the indirect

tensile strength requirements, cylinders 150 mm in diameter by 150 mm and 300 m m long were made and tested

at 7 and 28 days. The results of all the control tests are summarised and discussed in Section 3.

2.4.2 Reinforcement: In the CRCP sections with bar mat reinforcement the longitudinal steel consisted of hot-

rolled deformed ribbed bars (Type 2); the transverse steel was of indented steel except in the 230 mm thick section

with mid-depth reinforcement where Type 2 ribbed bars were used. The longitudinal and transverse reinforcement

in the 210 mm thick section with the fabric reinforcement consisted of indented wire.

3

The reinforcement mats were placed with the longitudinal steel on top, except on the Eastbound carriageway

between chainages 10157+00 and 10165+65. There the mats were inverted with the transverse wires on top,

including the additional bars, to maintain adequate depth of longitudinal joint groove. On the Westbound carriageway,

over this length, the mats were not inverted but the same additional transverse steel was placed on top of the

longitudinal steel.

The methods of fabrication and of positioning the steel reinforcement were deliberately made the

responsibility of the contractor so that he was free to suggest any suitable method by which the reinforcement

would be positioned at the specified level.

All the bar mats and mesh fabric reinforcement for the CRCP sections were prefabricated in 12m lengths,

approximately 2.2m wide; the standard mesh fabric for the conventional jointed reinforcement sections was in

mats 6.4m long by 1.8m wide. The contractor elected to use free-standing reinforcement. The original proposal

was to weld bent steel o f the appropriate height to the mats in the factory. Difficulties were experienced at a very

early stage in this process, both in obtaining the necessary height tolerances and in packaging for transport to the

site. A system using 'ring spacers' shown in Plate 2, was evolved and, after trials for stability and accuracy of position,

this method was adopted for both the CRCP and the conventional reinforced sections. The ring spacers consisted

of two steel wires with spacer bars o f the appropriate height welded to them at fight angles. The spacers were

delivered flat on site in 6m lengths and then bent into roughly circular or elliptical shapes prior to positioning

the reinforcement mats by crane (Plate 2). The reinforcement was secured to the spacers by wire ties and the

completed steelwork was very stable.

2.4.2.1 Laps: No laps were required in the transverse direction for either the continuous or the conventional

reinforcement. However, in the longitudinal direction an adequate length of lap is vital to obtain good performance.

For the conventional jointed reinforced pavement the minimum lap length was 450 nun with the first transverse

wire o f one mat lying within the last complete mesh of the previous mat. For the CRCP sections the laps in the

longitudinal steel were specified to be at least 35 times the bar diameter and to be so arranged that not more than

one-third occurred in any transverse section. The use of skewed laps was permitted but the contractor opted to use

right-angled laps; a typical layout o f the steel in a CRCP section is shown in Figure 2.

2.4.3 Joints: The following five types of joint were constructed in the carriageways:-

i) expansion

ii) contraction a) with normal width grooves

b) with narrow grooves

iii) wide flange beam

iv) construction (in CRCP)

v) longitudinal

2.4.3.1 Expansion joints: These joints only occurred between transition slabs and at the ends of CRCP where

anchorages were used. The expansion joints contained 32 m m diameter mild steel dowel bars, 750 mm long at

300 m m centres; the dowels were supported by prefabricated mesh cradles on either side of a 25 mm thick •ler

board o f Parana pine capped after concreting with a sandwich board of stiff hardboard enclosing expanded

4

polystyrene. One half of each dowel bar was debonded using a polyvinyl sheath with 25 mm expansion space at

the end. The joint assembly was fixed to the sub-base with long nails, to prevent movement during the passage of

the slip-form paver. After the concrete had hardened, the capping above the filler board was removed leaving a

30 mm wide sealing groove that was subsequently fiUed with caulking and a cold-poured seahng compound, a

two-part polysulphide-based material.

2.4.3.2 Contraction joints: All joints of this type contained 25 mm diameter mild steel dowel bars, 400 mm long,

spaced at 300 mm centres. They were debonded over half their length with polyvinyl sheaths and were supported

on prefabricated assemblies fixed to the sub-base with long nails. As construction took place during the summer

period, bottom crack-inducers were omitted and the surface grooves were formed either by the insertion of a two-

part plastic former into a wet-formed groove or by sawing; in all cases the depth of the groove was 75 ram,

ie 0.27 of the nominal slab depth.

Where the grooves were wet formed, the top part of the former was removed after the concrete had hardened

and the 10 mm wide groove was sealed with the cold-poured sealing compound. In one section of the unreinforced

construction the joint grooves were of the narrow unsealed type, formed by sawing 3 mm wide grooves at between

8 and 18 hours after compaction of the concrete. The sealing grooves for contraction joints in the conventional

reinforced sections were widened to 35 mm by sawing and were sealed with the cold-poured compound used for

the other transverse joints.

2.4.3.3 Wide-flange beam joints: These joints have not been constructed previously in this country although they

have been widely used in the USA; details of the joint are shown in Figure 3. The steel beam was fabricated to a

length 120 mm less than the width of the carriageway, to allow for manoeuvring of the slip-form paver, and was

galvanised to give added corrosion protection. Great care was necessary in setting the beam into the concrete

sleeper beam so that its top surface was at the correct finished road level; no particular difficulties were experienced

in paving up to and over this type of joint which was occasionally used as an end of day joint. The grooves at

these joints were later sealed with cold-poured sealing compound.

2.4.3.4 Construction joints in CRCP: These joints were necessary at the end of a day's work or when there had

been a breakdown in the paving process; they have been the cause of problems in CRCP construction previously.

Because the joint faces are smooth there is no aggregate interlock, such as exists at a crack, and load transfer at

the joints is thus less effective; strengthening and special care in construction are required at these positions.

Strengthening was achieved by the inclusion of extra longitudinal bars, 1.5m long, of the same size and type

as in the adjoining slab; this increased the percentage of steel at the joint to a minimum of 1.0 per cent. The

additional bars were placed centrally across the joint at the same level as the main longitudinal steel. Extra

compaction of the concrete in the congested area at the construction joints was needed. The longitudinal bars of

the CRCP were continued through these joints, for which a split timber stop-end was used. Construction joints

were not sealed.

2.4.3.5 Longitudinal joints: The two longitudinal joint grooves were wet-formed, dividing the carriageway into

three equal widths. Bottom crack inducers were not used and each joint groove was formed by the insertion o f

5 mm wide polyethylene strip, either 57 or 75 mm deep depending on the slab depth, using inserters mounted on

the rear o f the slip-form paver. In both the unreinforced and reinforced jointed sections tie bars of 10 mm diameter

deformed steel, 750 m m long at 600 mm centres, were cranked and connected by spacer bars into assemblies that

were secured to the sub-base in a similar manner to the transverse joint assemblies. No tie bars were used in the

CRCP sections as the transverse steel had been designed for this purpose; there was at least 500 mm of continuous

transverse steel on either side o f the longitudinal joint.

The longitudinal joint between the carriageway and hardshoulder was tied by three 16 mm diameter mild

steel bars, l m long at 900 mm centres, inserted by hand (in cranked shape) into the edge of the slab at the centre of

each hardshoulder bay.

2.4.3.6 Joints between concrete and flexible construction: Flexible construction was only used at the two

extremities o f the contract, over the two underbridges and for the slip roads at the interchange. A stepped

transitional slab (rolling block) was used except at the slip road/main carriageway joint; a section through this

slab is shown in Figure 4.

2.4.4 Surface texture: A brushed surface texture was achieved with a mechanically operated brush 3m wide.

The site is in an open rural area, and potential noise nuisance is therefore minimal. I f plastic grooving had, in fact,

been specified there is as yet no machine available for producing this texture when the slab is slip-formed.

2.5 Hardshoulder

Over the greater part o f the contract there is a trapezoidal-shaped drainage channel which the contractor

elected to form integrally with the hardshoulder. A small Guntert and Zimmerman slip-form paver was used for

this construction; texturing and application o f curing spray were done manually. The contraction joint grooves

were all sawn. Where transverse joints occurred in the conventional carriageway, they were matched for type and

position in the hardshoulder.

The concrete mix and the methods of mixing and transporting were the same as for the carriageway paving.

The slip-form paver operated f rom a single guide wire with one track of the paver running on the already completed

carriageway slab, protected f rom abrasion damage by the use of mats; the other track ran on the sub-base as

Shown on Hate 3. Prior to paving the hardshoulders, the cranked tie bars were straightened and any loose bars

were grouted with an epoxy resin grout. Polythene membrane was used under the hardshoulders except alongside

the lengths of carriageway from which the underlay was omitted.

The longitudinal joint between the carriageways and hardshoulders was sealed using a 25 mm deep by 5 mm

wide polyethylene strip secured to the top o f the carriageway edge with an adhesive. Transverse texture was

applied manually to the hardshoulders by wire-brushing.

Paving o f the hardshoulders commenced on 11 August 1978 and was completed by 15 September 1978;

the max imum length laid in one day was 1266m and the average daily output was 657m.

2.5.1 Transverse joints: As the hardshoulders were ofunreinforced concrete using a limestone aggregate, the

transverse joints were spaced at 6m intervals. Where there were joints in the carriageways the joints in the hard-

shoulders coincided both in position and type except at the wide-flange beam joints where expansion joints were

used in the hardshoulders. Alongside the CRCP sections all the transverse joints were of the contraction type.

The dowel bars in all the transverse joints were positioned in prefabricated assemblies secured to the sub-base and

the joint grooves were formed by sawing.

The transverse joints, except the wide contraction joints and all expansion joints where cold-poured sealants

were used, were sealed with hot-poured sealants.

3. TESTING AND CONTROL

Despite the experimental nature of the contract no special measures were adopted for control and testing, the

contract would thus be carried out under conditions similar to those experienced on normal construction sites.

There was extensive liaison between the site staff and TRRL but all the compliance testing and measuring was

undertaken by site staff. Copies of the paving records and the testing data have been made available to TRRL,

together with other relevant information. This will enable the future performance of the pavements to be closely

correlated to construction, material, and environmental factors. A summary has been made of the relevant

information and is presented below.

3.1 Sub-base

3.1.1 Granular sub-base material Type 1: This was a crushed limestone (dolomite) from South Yorkshire;

75 samples were tested by the client and the contractor also carried out many tests on the material. Most

samples complied with the specification although there were occasional problems with excess fines.

3.1.2 Cement-bound granular material: The aggregate used for this material was a screened slag from a near-by

steel works; 15 grading tests were made and, although the material generally complied with the specification, five

tests showed slight deficiencies in the percentage passing a 37.5 mm sieve. Again the contractor also carried out

many tests with satisfactory results.

Initially, a cement content of 7 per cent was used but, because of the high strength obtained, this was

progressively reduced to 4 per cent. The results of tests on cubes and cores are summarised in Table 2.

TABLE 2

Summary of test results on cement-bound granular material

Cement Cubes Cores

[ i Dry density content Compressive strength Dry density No. of cores (per cent) No. of cubes at 7 days (N/mm 2) (kg/m 3) (kg/m 3)

Note:

7 6 5.5 5 4.5 4

11 23 23 40 48 57

11.64 10.12 10.29

6.56 6.93 6.02

2221 2176 2233 2100 2145 2128

14 27 25 60 57 69

2200 2180 2182 2117 2191 2156

A cement content of 4 per cent was used for most of the sub-base.

The thicknesses of the two sub-base materials (cement-bound granular and Type 1 granular) were measured

in the core holes and are summarised in Table 3.

TABLE 3

Thicknesses of sub-base materials beneath CRCP sections

Carriageway

Westbound

Eastbound

Section

210 nun fabric

230 mm mid-depth

250 mm third-depth

250 mm mid-depth

210 mm third-depth

210 mm mid-depth

230 mm third-depth

No. of cores

35

41

47

31

31

23

28

Sub-base material thicknesses (mm)

Cement-bound granular material

152 (150)

147 (150)

154 (150)

137 (150)

Type 1 granular material

106 (100)

88 (80)

68 (60)

88 (60)

106 (100)

105 (100)

91 (80)

150 (150)

145 (150)

146 (150)

Overall

258 (250)

235 (230)

223 (210)

225 (210)

256 (250)

250 (250)

237 (230)

The figures in parentheses are the specified thicknesses.

3.2 Concrete carriageway slabs

Extensive testing was carried out both on the plastic concrete and on the hardened concrete. Measurements

were also made of the surface regularity and texture.

3.2.1 Plastic concrete: Tests were undertaken both by the contractor for quality control and by the client for

determining compliance with the specification. The results relating to particular experimental sections and

averages for the whole contract are given in Tables 4 and 5. The sections are listed in the order of paving. The

slump-test results are given in Table 4 and the air contents of the concrete in Table 5.

The values of slump shown in Table 4 indicate that a slightly less workable mix was used in the Eastbound

carriageway (with a much reduced variability) than in the Westbound carriageway. From Table 5 it can be seen

that the air content o f the concrete used in the Eastbound carriageway was significantly greater than in that used

for the Westbound carriageway (again with a reduced variability).

3.2.2 Hardened concrete: The indirect tensile test was used to measure the concrete strength and the

acceptance criterion was that the average of any four consecutive results should have a value of not less than

2.3 N/mm 2. Cylinders 300 mm long and 150 mm diameter were made and tested at 7 and 28 days during the

construction of the carriageways and hardshoulders; during the paving of the first (Westbound) carriageway,

150 mm long cylinders with a diameter of 150 mm were also made and tested at 28 days. Density measurements

were made on all the cylinders at the time of testing and the results of these measurements are summarised in

Table 6; the indirect tensile test results are summarised in Table 7.

TABLE 4

Summary of slump test results

Section

WESTBOUND CARRIAGEWAY 280 mm Unreinforced 210 mm CRCPofabric reinforcement 280 mm Reinforced 230 mm CRCP-mid-depth 250 mm CRCP-third-depth 250 mm CRCP-mid-depth Complete carriageway including transitions

EASTBOUND CARRIAGEWAY 280 mm Unreinforced with narrow

joints 280 mm Unreinforced 280 mm Reinforced 210 mm CRCP-third-depth 210 mm CRCP-mid-depth 230 mm CRCP-third-depth Complete carriageway including transitions

BOTH CARRIAGEWAYS

Length (m)

No.

678 30 1572 29 504 15

1695 30 1689 35 1746 31

8279 186

678 14

1632 29 504 8

1698 24 1692 19 1746 17

8279 118

16558 304

Client's tests

Average S.D.* (mm) (mm)

34.0 20.1 17.5 10.8 21.3 9.2 22.7 12.2 44.0 45.0 35.3 25.5

29.0 26.4

26.8 12.2

26.2 11.6 21.9 8.0 19.6 10.1 30.5 14.3 23.8 11.0

24.7 I 1.8

27.3 22.0

* Standard deviation TABLE 5

Summary of air content test results

No.

15 22

7 21 24 21

120

10

23 7

22 22 24

114

234

Contractor's tests

Average S.D.* (mm) (mm)

38.5 15.2 26.8 20.5 21.4 5.6 21.0 8.8 21.5 12.5 25.7 8.6

24.9 14.1

18.0 6.8

18.9 6.6 20.0 5.8 22.3 9.8 25.0 9.1 20.4 8.1

21.2 8.3

23.1 t l . 8

Section

WESTBOUND CARRIAGEWAY 280 mm Unreinforced 210 mm CRCP-fabric reinforcement 280 mm Reinforced 230 mm CRCP-mid-depth 250 mm CRCP-third-depth 250 mm CRCP-mid-depth Complete carriageway including transitions

EASTBOUND CARRIAGEWAY 280 mm Unreinforced with narrow

joints 280 mm Unreinforced 280 mm Reinforced 210 mm CRCP-third-depth 210 mm CRCP-mid-depth 230 mm CRCP-third-depth Complete carriageway including transitions

BOTH CARRIAGEWAYS

Length (m) No.

Client's tests

Average S.D.* (%) (%) No.

678 25 3.5 2.0 15 1572 22 4.0 0.7 21

504 10 4.0 0.8 8 1695 23 3.6 1.5 21 1689 24 4.6 0.8 24 1746 23 4.4 0.8 20

8279 142 4.0 1.3 119

* Standard deviation

678 9 4.2 0.7 10

1632 23 4.7 0.9 23 504 7 5.0 0.6 7

1698 20 4.8 0.7 22 1692 19 5.0 0.8 21 1746 11 4.0 0.7 24

8279 93 4.7 0.8 113

16558 235 4.3 1.1 232

Contractor's tests

Average [ S.D.* (%) (%)

3.8 O.6 3.6 0.5 3.8 0.7 3.7 0.7 3.9 0.8 3.8 0.6

3.8 0.6

4.3 0.7

4.0 0.8 4.7 0.6 4.5 0.8 4.3 0.6 4.0 0.6

4.2 0.7

4.0 O.7

9

TABLE 6

Summary of concrete density measurements

Section

WESTBOUND CARRIAGEWAY

280 m m Unreinforced

210 m m CRCP-fabric reinforced

280 m m Reinforced

230 m m CRCP-mid-depth

250 m m CRCP-third-depth


Complete carriageway including transitions

EASTBOUND CARRIAGEWAY

280 m m Unreinforced with narrow joints

280 m m Unreinforced

280 nun Reinforced




Complete carriageway including transitions

BOTH CARRIAGEWAYS

300 m m long cylinders 150 mm long

cylinders

7 day tests 28 day tests 28 day tests

Average Average No. No. (kg/mJ) No. (kg/m3)

16

24

7

23

24

22

126

10

23

7

22

22

24

114

Average (kg/m ~)

2340 16

2364 42

2344 14

2356 14

2350 48

2354 42

2352 225

2345 10

2347 23

2323 7

2331 22

2316 22

2315 24

2329 114

2341 339

2342

2362

2356

2360

2354

2355

2356

2343

2342

2325

2339

2319

2318

2331

2348

40

14

46

48

40

202

240

2362

2359

2362

2362

2361

2362

10

Z

5 Z

d ' - "

z

e- N

;~ rd "-"

0

.o

0 0 0 0 0 0

~ 0 ~ ~ 0 ~

0 ~ 0 ~ ~ 0

o o o o o o o o o o o o o o

o o o o o o o o o o o o o o o

~ o

o ~: =

~ ~ c~ ~ ~-, ~ ~ . o ~ ~ ~ c~ ~ ~

o o o o o o -~ o o o o o o

("4

c5

~ 0

c ~

~ 0

c ~

0 0

O~

0

~ 0

c ~

o = o 0

l l

Table 6 shows that densities in the second (Eastbound) carriageway were slightly lower probably because of

the increased air content; the higher density measured in the 150 rnm long cylinders possibly indicates that better

compaction was achieved in these specimens than in the 300 mm long cylinders.

All the concrete strength tests for both carriageways and hardshoulders complied with the specification. The

reduced 7 and 28 day strength results obtained on the second (Eastbound) carriageway were the result of the

higher level of entrained air. The variability of the concrete, as evidenced by the coefficients of variation, was

higher than would be expected on a large contract; the explanation for this is probably that control of concrete

quality was effected by means of the Slump Test which is insensitive for controlling workability of PQ concrete.

3.2.2.1 Cores: A total o f 94 cores was taken from the carriageway slabs to check the depth and state of

compaction of the concrete and, where appropriate, the positions of reinforcement, dowel and tie bars. The

concrete in all the cores was well compacted, even in one 450 mm deep taken from above a keyway in one of the

anchorages. The average excess of slab thickness over that specified was 10 mm and all the cores showed thicknesses

within the tolerance allowed (15 mm less than nominal). The slab thicknesses of the experimental sections and

reinforcement depths, where appropriate, are summarised in Table 8. The position of the reinforcement appears

to be lower than intended; this is discussed in Section 5.1.2.

TABLE 8

Summary of core results

Section

Slab thickness Reinforcement depths

No. Average Max. Min. of Specified Average Max. Min.

(mm) (mm) (mm) (rnm) (mm) (mm) (mm) cores

No.

of cores


280 mm Unreinforced 14 290 317 265

210 mm CRCP-fabric reinforcement 11 234 255 225 10 105

280 mm Reinforced 2 285 295 275 1 60

230 mm CRCPomid-depth 12 234 270 215 8 115

250 mm CRCP-third-depth 11 256 270 237 11 90

250 mm CRCP-mid-depth 13 250 265 235 13 125


280 mm Unreinforced with narrow 3 313 332 275

joints

280 mm Unreinforced 4 288 298 280

280 mm Reinforced 2 295 305 285 2 60


210 mm CRCP-mid-depth 4 233 245 210 4 105


125

65

126

96

125

68

85

122

90

145 115

155 105

110 80

140 107

75

100

140

113

60

75

100

77

12


3.2.3.1 Surface regularity: The specified tolerances for longitudinal surface regularity were those in the Ministry

of Transport Specification 2, ie up to 20 irregularities are permitted to exceed 3 mm, up to 2 irregularities to exceed

6 mm and none to exceed 10 mm in a length of road of 300m, as measured by the rolling straight-edge. During

the currency of the contract the revised Department of Transport Specification 3 was published in which the 3 mm

and 6 mm tolerances were raised to 4 mm and 7 mm respectively. The results of the rolling straight-edge tests are

summarised in Table 9 in terms of both specification tolerances. These results show poor comphance with the

earlier specification but relatively good compliance with the later one. The results have not been analysed in the

different experimental sections because the effect of 'reinforcement ripple', discussed in Section 5.1.3, cannot be

readily detected by the rolling straight-edge.

TABLE 9

Summary of roiling straight-edge tests

Carriageway

WEST- BOUND

EAST- BOUND

Lane

Left- hand

Centre

mght- hand

All

Left- hand

Centre

mght- hand

All

Length* tested (m)

2920

8278

1120

12318

2800

6941

4471

14212

No. of runs*

10

31

4

45

10

24

16

50

DOE Specification

No. passing

3

9

2

14

Per cent

30

29

50

31

10

54

19

34

DTp Specification

No. passing

9

28

4

41

1

13

3

17

7

20

9

36

q Per cent

90

90

100

91

70

83

56

72

BOTH , All I 26530 : 95 1, 31 33 77 81

* Length of run was generally 300m but some lengths were tested twice.

Three additional methods of measuring the surface profile were used to assess the riding quality of the surface.

The surface irregularity indices, q, obtained by the multi-wheeled prof'flometer are shown in Figure 5. Taking an

index, q, of 65 cm/km or less as indicating a very good quality of ride 4, 41 out o f the 70 measurements (58 per

cent) fall within this category and only 7 measurements (10 per cent) have an index of greater than 120 cm/km;

this would be classed as fair.

Two other methods of measuring surface irregularity, the High-Speed Profilometer, developed at TRRL 5,

and the Bump Integrator, were also used; the results obtained are given in Table 10.

13

TABLE 10

Results obtained using the high-speed profilometer and bump integrator ('r' value)

Section


280 mm Unreinforced

210 mm CRCP-fabric reinforcement

280 mm Reinforced

230 mm CRCP-mid-depth

250 mm CRCP-third-depth



280 mm Unreinforced with narrow joints

280 mm Unreinforced

280 mm Reinforced




Lane

Left-hand Centre Right-hand




Left-hand Centre

Left-hand Centre

Left hand Centre Right-hand




Left-hand Centre

Left-hand Centre

r

(cm/km)

197 222

150 152

205 216

158 174

177 193

161 167

189 194

170 178

193 219

170 178

182 177

215 196

3m [ 5m (mm) (mm)

0.79 0.93 0.96 1.17 0.91 1.09

0.61 0.85 0.63 0.84 0.63 0.82

0.81 0.94 0.95 1.06 0.95 1.09

0.68 0.84 0.76 0.91 0.80 0.95

0.83 1.05 0.88 1.08

0.65 0.79 0.72 0.87

0.79 0.91 0.80 0.95 0.83 0.92

0.73 0.89 0.82 1.01 0.85 1.04

0.79 0.97 0.86 1.03 0.86 1.05

0.74 0.96 0.81 1.06 0.83 1.10

0.83 0.87 0.77 0.98

0.96 1.17 0.96 1.29

Standard deviation under moving average lengths of:

I (run)

1.12 1.39 1.31

1.16 1.37 1.30

1.27 1.35 1.44

1.17 1.26 1.28

1.37 1.49

1.18 1.24

1.14 1.25 1.25

1.15 1.36 1.44

1.38 1.36 1.39

1.55 1.62 1.73

1.20 1.45

1.66 2.02

The bump integrator readings show that none o f the experimental lengths are 'very good' ('r' less than

145 cm/km) but 20 o f the readings (83 per cent) are less than 210 cm/km and are considered to be 'good'. With

two exceptions all the results hldicate a lower value for the left-hand lane than for the centre lane.

14

In assessing the results from the High-Speed Profdometer it has been assumed that a moving-average length o f

3m provides a profde datum that approximates to that of the rolling straight-edge and experience has shown that a

standard deviation of the profde about this datum of less than 1 mm indicates compliance with the Department of

Transport's straight-edge specification 3. On this basis all the sections would be acceptable; again the near-side lane

tends to have the lowest values, ie the best riding qualities. All the measures of irregularity so far considered are

related to relatively short wave lengths. The standard deviations of the profde about a moving average of 10m are a

measure of longer wave lengths and the results given in Table 10 again show the left-hand lane to have the lowest

values.

From the various irregularity measurements, the best riding quality occurred on the 210 mm thick CRCP

section with fabric reinforcement, followed by the 250 mm and 230 mm thick CRCP sections with reinforcement

at mid-depth. The worst riding qualities were given by the two jointed reinforced sections and the 250 mm thick

CRCP section with reinforcement at third-depth, worst of all being the 230 mm thick CRCP section with

reinforcement at third-depth. The effect of reinforcement on surface regularity is discussed in Section 4.1.3.

It was anticipated that the unreinforced section with narrow unsealed transverse joint grooves would have a

superior riding quality to that of the unreinforced sections with normal width wet-formed joint grooves. This has

not proved to be the case because, although the values for the section with narrow grooves are better than those

of the unreinforced section on the Westbound carriageway (including the trial length), they are not as good as

those for the longer unreinforced section on the Eastbound carriageway. This indicates that wet-formed joints can

be formed and recompacted without detriment to the riding qualities of the slab.

3.2.3.2 Surface texture: The Specification requirement for surface texture 2 was that the average value for each

set of 10 sand-patch tests should be not less than 0.75 mm and that there should be not more than one test of each

set with a value of less than 0.65 mm. The results of the tests made on the carriageway slabs are given in Table 11 ;

most of the tests were made on areas where there were doubts about the texture.

TABLE 11

Results of surface texture measurements (on doubtful areas)

Carriageway

WESTBOUND

EASTBOUND

BOTH

No. of test sets

37

38

75

No.

27

26

53

%

73

68

71

Passing Average texture depth (mm)

1.01

0.94

0.97

Approximately one-third of the values failing to meet the specification were the result of the average value

being less than required; the minimum average value for texture depth was 0.57 mm.

15

3.3 Concrete slabs in hardshoulders

3.3.1 Plastic concrete: The results of the Slump Tests are given in Table 12.

TABLE 12

Summary of Slump Test results on hardshoulder concrete

Client's tests Contractor's tests

Carriageway l No. Average S.D.* No. Average S.D.*

(mm) (mm) (mm) (mm)

WESTBOUND

EASTBOUND

BOTH

56

44

100

28.8

24.8

27.0

16.4

11.9 14.7

65

56

121

25.5

22.0

23.9

10.4

9.8

10.2


The concrete used in the hardshoulders had very similar workabilities, as measured by the Slump Test, to

that used in the carriageways (see Table 4) but with reduced variabilities.

A summary of the air content test results is given in Table 13.

TABLE13

S u m m a r y o f a i r c o n t e n t t e s t r e s u l t s ~ r h a r d s h o u l d e r c o n c r e t e

Carriageway

WESTBOUND

EASTBOUND

BOTH

No.

50

43

93

Client's tests

I Average (%)

4.7

4.2

4.5

S.D.* (%)

0.9

0.9

0.9


No.

65

56

121

Contractor's tests

Average S.D.* (%) (~)

4.4 0.9

3.8 1.0

4.1 1.0

3.3.2 Hardened concrete: For the hardshoulder concrete only cylinders 150 mm diameter and 300 mm long were

used. The density results are summarised in Table 14 and the indirect tensile strength tests are summarised in

Table i 5.

16

TABLE 14

Summary of density measurements on concrete for hardshoulder

Carriageway

WESTBOUND

EASTBOUND

BOTH

No.

65

56

121

7 day tests

Average (kg/m ~ )

2311

2335

2322

No.

65

50

115

28 day tests

Average (kg/m ~)

2317

2343

2328

TABLE 15

Summary of indirect tensile strength results o f hardshoulder concrete

Carriageway No.

WESTBOUND 65

EASTBOUFrD 56

BOTH 12 l

* Standard deviation ** Coefficient of variation

7 day tests

Average S.D.* C.V.** (N/mm 2) (N/mm 2) (%)

2.58

2.85

2.70

0.31

0.32

0.35

12.0

11.2

13.0

No.

65

56

121

28 day tests

Average S.D.* C.V.** (N/mm 2) (N/mm 2) (%)

3.01

3.15

3.07

0.36

0.28

0.34

12.0

8.9

11.1

The densities of the concrete were similar to those of the concrete in the Eastbound carriageway; the average

tensile strengths at both 7 and 28 days for the Eastbound hardshoulder were very similar to those for the Eastbound

carriageway but the strengths obtained from concrete in the Westbound hardshoulder were somewhat lower. The

variability of concrete strengths was less than that observed in the carriageway paving.


3.3.3.1 Surface regularity: The regularity requirements of the specification for the hardshoulders were less

rigorous than those for the carriageway; no measurements were made.

3.3.3.2 Surface texture: The surface of the hardshoulders was textured by transverse brushing with a wire broom.

The specification contained no minimum texture-depth requirements.

4. REMEDIAL ACTIONS

In Section 3.2.3, mention was made of non-compliance with the surface regularity and texture requirements of

the specification. Remedial action was taken to improve the riding quality and resistance to skidding over only

0.45 per cent of the paved area. Regularity was improved by 'bump cutting' using a small flailing machine to

remove highspots; six short lengths were treated. The same machine, with the flails arranged to form random

spaced transverse grooves, was used to retexture the areas of low texture depth.

17

At ten joints in the hardshoulder, alongside the conventionally reinforced section in the Westbound carriage-

way, there was a delay in sawing the joint grooves and uncontrolled cracking resulted. Where the cracks were more

than 200 mm away from the centre-line of the joint, they were repaired using the accepted method of inserting

dowel bars. Where the joint grooves were required to be wider than 10 mm, at expansion joints and at the

contraction joints alongside the conventionally reinforced sections, the initial saw cut was subsequently widened.

5. COMMENTS ON CONSTRUCTION

No abnormal difficulties were experienced during the construction of the CRCP sections either by the contractor

or by the client. As in all paving work, good pre-planning and an efficient organisation are necessary if paving is to

proceed rapidly and to specification. In the M 180 neither the anchorages nor the wide-flange beam joints posed

difficulties, although the latter required very careful setting-out to ensure that the beams were at the correct level.

In a CRCP road the reinforcement needs to be positioned well ahead of the paving operation; similarly, in a

jointed pavement the transverse joint assemblies must be erected and tested well in advance of paving when a slip-

form paver is used. For the experirnental sections the average forward speed of the slip-form paver was approx-

imately 1.0m per minute. The lowest average speed achieved was 0.5m per minute for the unreinforced section on

the Westbound carriageway (this included the trial lengths). The fastest progress was in the 210 mm thick CRCP

section with mid-depth reinforcement for which the average speed was 1.3m per minute (this included the record

daffy output of 1132m). Obviously, the rate of paving is influenced by weather conditions and the distance of the

paving site from the hatching plant but if the overall rates of progress are examined, ie including joint forming,

texturing and application of curing compound, the rates are generally higher for the CRCP sections than for the

jointed paving.

5.1 Tolerances

5.1.1 Slab thickness: The slab thicknesses deduced from dip measurements made before and after paving, at 2m

intervals across the carriageways from wires spaced at 6 metre hatervals along the carriageways, showed close

agreement with the nominal thicknesses. The core results (Table 8), however, indicated thicknesses somewhat

greater than those specified. The reasons for this difference cannot be explained; however the cores represent

a very small proportion o f the carriageway area and may be unrepresentative.

5.1.2 Reinforcement position: In all, 51 cores were taken from the CRCP sections. A tolerance of + 10 mm

was permitted in the Specification for experimental purposes and in 26 (51 per cent) of the cores, the reinforcement

was outside the tolerances allowed.

In a system of construction using free-standing reinforcement the position of the steel and its tolerances will

normally be governed by the accuracy of the sub-base levels and reinforcement supports; in the M180 specification,

the tolerances for sub-base levels were + 20 mm. A contractor using free-standing reinforcement must either ensure

that the accuracy of laying of the sub-base is to the tolerances required for the reinforcement or ensure that the

reinforcement level is a fixed distance below theoretical pavement level by adjusting the supports. Had the

reinforcement been specified in this instance as a certain height above the base of the slab, then in only 7 (14 per

cent) o f the cores would it have been outside the tolerances of + 10 mm.

18

5.1.3 Reinforcement ripple: This effect, mentioned earlier in Section 3.2.3.1, is the reflection on the finished

slab surface of the pattern of the reinforcement in the form of shallow depressions, usually less than 3 m m in

depth. The exact cause of reinforcement ripple is not fully understood but it is believed to be due to further

vibration transmitted to the reinforcement after the passage of the paver; this extra vibration, o f a high frequency,

causes further consolidation of the concrete immediately above the reinforcement bars or wires and thus the

depressions in the surface.

The depressions above the longitudinal bars do not cause any inconvenience to traffic but those above the

transverse bars, because of their regular spacing, can initiate vibrations in vehicles which at certain speeds induce

drumming. The presence of reinforcement ripple can be detected by the m~dti-wheeled and high-speed

profdometers and examples of profiles obtained from the latter machine are shown in Figure 6.

The occurrence of ripple is influenced by a number of factors; these include direction, amplitude and frequency

of the applied vibration in the paver, depth of reinforcement, diameter and spacing of the bars, and workability

of the concrete. Ripple can occur with conventional reinforced pavements as well as in CRCP and it is present in

the conventionally reinforced concrete sections of M180.

The possibility of ripple occurring was considered beforehand and for this reason the specification required

the transverse bars to be placed beneath the longitudinal reinforcement. A detailed analysis of reinforcement ripple,

and the factors causing it on this section, has not been possible because no measure of ripple was available, there

was little information on reinforcement depth and because the Slump Test was insensitive as a measure o f work-

ability. A regression analysis of the average reinforcement depth in the CRCP sections (from the cores) against the

standard deviation under a moving 3m length showed the relationship to be significant at between the 5 and the 10

per cent levels; the standard deviation decreased with increasing depth of reinforcement.

Subjectively, the worst lengths for reinforcement ripple are at the eastern ends of bo th carriageways. Here,

extra 16 mm diameter deformed bars were placed across the top of the bar mats to strengthen the slabs against

the expected settlement over an area of peat; also at the eastern end of the Eastbound carriageway the bar mats

were inverted with the transverse bars on top so that a longitudinal joint groove of adequate depth could be formed.

As a result o f the occurrence of ripple the design recommendations for future CRCP have been amended

to specify a closer spacing of smaller diameter bars for transverse reinforcement.

5.1.4 Omission of separation membrane: The occurrence of cracking at the joints in the unreinforced section

with narrow unsealed transverse joint grooves was monitored to observe whether the omission of the separation

membrane had an effect on the rate of cracking. At 3 days, 35 per cent o f the joints where there was no membrane

had cracked compared with 25 per cent of the joints where the membrane was included; at 14 days the respective

percentages were 50 and 44. This limited evidence suggests that the omission of the membrane promotes earlier

cracking at the transverse joints; this should be associated with a more uniform joint movement during the life

of the pavement.

19

6. COSTS

When a large number of variables are incorporated in a full-scale experiment, costs are likely to be masked by the

need for changes in thickness and materials. The tender rates for the six contractors have been compared in Table 16

on the basis that the control sections of 280 mm thick unreinforced slabs with sealed joints have a value of 100;

the comparison includes the tender rates for sub-bases.

TABLE 16

Comparison of tender rates for different forms of construction

Construction type

280 mm Unreinforced

280 mm Unreinforced with narrow joints

280 mm Unreinforced with narrow joints no underlay

280 mm Reinforced

210 mm CRCP fabric reinforcement

210 mm CRCP bar mat reinforcement



1

100

99.7

99.1

110.2

104.2

106.4

114.2

118.0

Tender rates for contractor

2

100

97.7

96.6

116.6

118.7

121.6

126.6

132.3

3

100

100.0

99.3

109.2

121.4

124.2

127.9

130.8

4

100

103.0

102.4

110.9

118.7

121.1

127.7

131.0

5

100

98.8

97.8

116.5

124.9

127.4

125.2

126.3

6

100

99.6

98.3

124.8

140.9

142.6

149.8

154.1

Average

100

99.8

98.9

114.7

121.5

123.9

128.6

132.1

As was to be expected, there was a wide divergence in the actual tender rates submitted by the six contractors

but all priced the 250 mm CRCP as the most expensive and, with one exception, the 280 mm unreinforced with

narrow joint grooves and no separation membrane as the cheapest. Contractor 4 obviously priced joifat sawing

much higher than the other contractors; it is not known how the contractors other than the successful one intended

to carry out the work. The difference between jointed unreinforced and CRCP construction will reflect the relative

prices o f concrete and steel. On the basis o f the M180 prices it would appear that, for a steel content of 0.6 per

cent, a 70 mm reduction in slab thickness for CRCP will cost between 5 and 20 per cent more than a conventionally

jointed unreinforced pavement; for a 50 mm thinner CRCP slab, the extra paving cost will be between 15 and 30

per cent and for a 30 mm thinner CRCP slab the extra cost will be between 20 and 35 per cent.

More realistic costs of CRCP will be obtained from normal contracts without experimental variations.

7. PERFORMANCE

Paving of the carriageways was completed on 5 August 1978 and that of the hardshoulders by 15 September 1978.

The western half of the section, ie up to the A161 interchange was opened to traffic in October 1978 and the

remaining length was opened on completion of the Trent Bridge in July 1979.

20

Performance of the CRCP sections will be assessed from crack surveys made at regular intervals; early

indications are that the optimum average spacing of transverse cracks of between 1.5 and 2.5m will be achieved.

8. ACKNOWLEDGEMENTS

The work described in this report forms part of the research programme of the Construction and Maintenance

Division (Division Head: Mr P D Thompson) of the Highways Department of TRRL.

The willing co-operation of the staff of the West Yorkshire Metropolitan County Council Sub-Unit (Chief

Engineer: Mr J A Gaffney) and of Sir Alfred McAlpine and Son (Northern) Limited is very gratefully acknowledged.

9. REFERENCES

1. GREGORY, J M. The design of experimental concrete carriageways on M180 (Sandtoft to Trent Section).

Department of the Environment Department o f Transport, TRRL Report SR 653. Crowthorne, 1981

(Transport and Road Research Laboratory).

. MINISTRY OF TRANSPORT. Specification for road and bridge works. Fourth edition. London, 1969

(H M Stationery Office).

. DEPARTMENT OF TRANSPORT. Specification for road and bridge works. Fifth edition. London, 1976


4. DEPARTMENT OF TRANSPORT, TRANSPORT AND ROAD RESEARCH LABORATORY and

CEMENT AND CONCRETE ASSOCIATION. A guide to concrete road construction (Third edition).

London, 1978 (H M Stationery Office).

5. DEPARTMENT OF THE ENVIRONMENT DEPARTMENT OF TRANSPORT. Transport and Road

Research 1976. Annual Report of the Transport and Road Research Laboratory. London, 1977


21

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Neg. no. R132/80/11

Plate 1 Guntert and Zimmerman slip-form paver laying 3-lane carriageway (The section being laid is 280mm thick reinforced jointed pavement)

Neg. no. R 132/80/4

Plate 2 Completed reinforcement showing ring spacers in use. (Section is 210mm thick CRCP with mesh fabric reinforcement)

Ne9. no. R132 /80 /13

Plate 3 Small G & Z slip-form paver laying hardshoulder and integral trapezoidal drainage channel

( 1 5 6 2 ) D d 8 0 4 1 3 0 1 1 , 5 0 0 9 /81 l - tPL td So ' t ( )n ( 3 1 9 1 5 P R I N T E D IN E N G L A N D

ABSTRACT

THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M180 (SANDTOFT TO TRENT SECTION): J M Grego~ FIHE: Department of the Environment Department of Transport, TRRL Supplementary Report 682: Crowthorne, 1981 (Transport and Road Research Laboratory). This report describes the construction of the experimental concrete carriageways on the Sandtoft to Trent section of M180; the design of the experiment has been reported in SR 653.

Construction of the 11.2m wide concrete carriageways was carried out in one operation by a slip-form paver. The maximum length laid in one day was 1132m and an average daily output o f 502m was achieved. The hardshoulder was also paved in concrete by a small slip-form paver which formed the integral drainage channel.


ISSN 0305-1315

ABSTRACT

THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M180 (SANDTOFT TO TRENT SECTION): J M Gregory FIHE: Department of the Environment Department of Transport, TRRL Supplementary Report 682: Crowthorne, 1981 (Transport and Road Research Laboratory). This report describes the construction of the experimental concrete carriageways on the Sandtoft to Trent section of M180; the design of the experiment has been reported in SR 653.

Construction of the 11.2m wide concrete carriageways was carried out in one operation by a slip-form paver. The maximum length laid in one day was 1132m and an average daily output o f 502m was achieved. The hardshoulder was also paved in concrete by a small slip-form paver which formed the integral drainage channel.


ISSN 0305-1315

transport and road research laboratory …the length of unreinforced pavement with narrow unsealed...

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