TRANSPORT and ROAD RESEARCH LABORATORY
Department of the Environment
TRRL SUPPLEMENTARY REPORT SR 22 UC
THE DESIGN OF ROLLED ASPHALT: A FULL-SCALE EXPERIMENT ON A33 WINCHESTER BY-PASS 1972
by
M.E. Daines
Any views expressed in this Report are not necessarily those of the Department of the Environment
Materials Division Highways Department
Transport and Road Research Laboratory Crowthorne, Berkshire
1974
CONTENTS
Abstract
1. Introduction
2. Composition of the asphalts
2.1 Materials
2.1.1 Coarse aggregate 2.1.2 Fine aggregates 2.1.3 Filler 2.1.4 Binder 2.1.5 Coated chippings
2.2 Composition of mixtures 2.3 Rate of spread of coated chippings
3. Site of the experiment
4. Mixing and laying
4.1 Mixing 4.2 Laying 4.3 Chipping 4.4 Rolling 4.5 Appearance of the asphalt after laying 4.6 Summary of weather conditions during laying work
5. Initial results
5.1 Analysis of mixtures laid on A33 Winchester By-pass 5.2 Summary of observations and measurements
6. Future work
7. Acknowledgements
8. Reference
9. Appendix 1 - Sands used for the full-scale experiment on A33 Winchester By-pass
10. Appendix 2 - Composit ion of mixtures laid on A33 Winchester By-pass
11. Appendix 3 - Diary of events
Page
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4 5 5 5 6 6
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( ~ CROWN COPYRIGHT 1974
Extracts may be quoted, except for commercial purposes, provided the source is acknowledged
Ownership of the Transport Research Laboratory was transferred from the Department of Transport to a subsidiary of the Transport Research Foundation on I 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.
THE.DESIGN OF ROLLED ASPHALT: AFULL-SCALE EXPERIMENT O N A 3 3 WINCHESTER BY-PASS 1972
ABSTRACT
The laying of rolled asphalt designed using the Marshall Test in a full-scale experiment on the A33 Winchester By-pass, 1972, is described. Eight sands, covering a wide range of grading, particle shape, opt imum Marshall Stability and optimum binder content (some being outside the grading limits of BS 594:1961) were used to produce 30% stone-content rolled asphalt wearing courses. Asphalt for each sand was laid with five binder
contents; optimum, optimum + 0.75 per cent, and opt imum + 1.5 per cent. The experimental sections will be studied by measurements of transverse profile, sideway force coefficient and texture depth.
1. INTRODUCTION
Hot rolled asph',dt has been in use as a wearing course for many years in the UK and is at present specified in BS 594:1961. The development of this material has been largely the result of experience in use coupled with the results of full-scale experiments. At present the British Standard presents the specifications as ' recipe ' mixtures without reference to design tests for the asphalt. The contents of coarse aggregate, binder and filler are specified in ranges which have in the past produced durable rolled asphalts with a useful life of 15 to
20 years.
With increasing volume and load of traffic the problems of maintaining resistance to deformation, resistance to skidding, texture depth and durability have been accentuated. In recent discussions for the revision of BS 594 the British Standards Committee was aware of the need to improve.the overall performance and considered that the type and grading of the sand had a marked effect on the binder requirements and properties of a mix. It has been the practice of the industry to select, from within thespecifications, sands that are known to produce satisfactory asphalts. There is, therefore, little road evidence of the behaviour of asphalts containing sands that although complying with the specification are not considered suitable for the binder contents required in BS 594. Also there are sands outside the grading specification of BS 594 that
may produce good asphalts.
In order to produce a satisfactory design procedure for determining the opt imum binder content o f rolled asphalt it is necessary to determine the practical optimum from road performance. The 1971 edition of Road Research 1 mentions proposals for a full-scale experiment to examine rolled asphalt wearing courses designed using the Marshall Test, the main objectives being to examine whether the op t imum binder content as determined by the Marshall Test gives optimum road performance and whether sands requiring a binder content outside the ranges specified in BS 594:1961 can be used to produce satisfactory road surfacings. Rolled asphalts containing 30 per cent of coarse aggregate and eight different sands, each with a range of binder contents, were laid on A33 Winchester By-pass in June and July 1972. The sands were chosen to cover a wide range of gradings, surface textures and 'Marshall' stabilities. The ranges of binder contents selected for each of the sands were determined using a draft design procedure proposed for the revision o f BS 594. Other procedures will be investigated using the aggregates employed in the experimental mixtures.
This Report describes the selection and laying of the asphalts for the full-scale experiment.
2. COMPOSITION OF THE ASPHALTS
2.1 Materials
The manufacture of the asphalts was carried out using the following constituents:-
2.1.1 Coarse aggregate
Basalt from Moonshill Quarry, Somerset (SG 2.77).
2.1.2 Fine aggregates
1. Croxden sand (SG 2.67)
2. Fairoak sand (SG 2.67)
3. Hilton sand (SG 2.66)
4. Rockbeare sand (SG 2.66)
5. Chertsey sand (SG 2.67)
6. Durham sand (SG 2.65)
7. Redhill 65 sand (SG 2.66)
8. Mersey sand (SG 2.66)
These sands are all siliceous; the gradings are given in Table 1 and a fuller description is given in Appendix 1.
2.1.3 Filler
Crushed limestone from Flowers Ltd (SG 2.70; Bulk density in toluene 0.66 g/ml; 88 per cent passing 75 /am sieve).
2.1.4 B i n d e r
Petroleum bi tumen from Middle East crude source 50 pen. grade. R & B softening point 56. Penetration Index = 0. Permittivity 2.685 at 25"C.
2.1.5 Coated chippings
Sandstone (greywacke) from Craig-yr-Hesg Quarry, Pontypridd, Glam. PSV 67*; Flakiness Index = 10.
Grading: 100 per cent passing 28 mm BS sieve 97 per cent passing 20 mm BS sieve 28 per cent passing 14 mm BS sieve
2.2 Composition of mixtures
For each sand the proportions of coarse aggregate, fine aggregate and filler were maintained constant such that the stone content was close to 30 per cent of the total mix and the amount of aggregate passing a 2.36 m m sieve and retained on a 75/am sieve was six times the amount passing a 75/am sieve, i.e., the sand/
filler ratio was 6:1.
The range of binder contents selected for each type of sand was selected from the draft procedure proposed for the revision o f BS 594. The target opt imum binder contents for the asphalts made with each type o f sand are given in Table 1 and in addition mixtures with binder contents of target + 0.75 and + 1.5 per cent were manufactured.
* This value is not necessarily typical o f current production
2.3 Rate of spread of coated chippings
The coated chippings were spread at a target rate of 11 kg/m 2.
TABLE 1
Grading of the stockpile sands*, and opt imum binder contents
Grading Croxden %
passing
5 mm 100
2.36 mm 100
1.18 mm 100
600/am 100
425/am 99
300/am 91
212/am 53
150/am 28
75/am 2.4
Optimum binder con- tent of sand/ 13.1 filler/bitu- men (per cent)
Stability N** 5490
Target optimum 9.9 for expt***
Fairoak Hilton Rockbeare Chertsey Durham Redhill Mersey
100 100 100 100 100 100 100
100 98 100 85 99 100 100
99 95 99 74 98 100 99
98 86 97 59 73 97 99
96 76 92 44 55 91 98
90 49 70 25 40 78 93
50 21 33 8 24 50 26
20 12 18 4 16 30 7
0.6 1.8 2.9 0.6 1.2 0.5 0.8
11.5 8.2 12.5 7.5 8.3 9.3 9.6
4460 5580 7010 5310 6310 4030 2920
8.7 6.4 9.4 5.9 6.5 7.2 7.4
Specification
100
95-100
75-100
m
15-60
m
0-5
* Details of sand source and type are given in Appendix 1.
** This is the 'Marshall' stability determined on the sand/filler/binder system.
*** For 30% coarse aggregate content. The specified range of binder content in BS 594 is 7.4-8.4 per cent
for Schedule 1.
3
3. SITE OF THE EXPERIMENT
The site chosen for the experiment was the de-restricted northbound carriageway of the A33 Winchester By- pass (see Fig. 1). Although the site was not ideally straight and level, the bends and gradients were considered to be within acceptable limits. The site is traversed by the A333 road into Winchester. There are traffic lights at this junction. The dual carriageway is mostly in cut for the length of the experiment. The road was originally of concrete construction and had been overlaid with asphalt which was subsequently surface dressed. Prior to the experimental work some reconstruction was carried out, the road being widened to 6.4 m and kerbs being replaced. New rolled asphalt base-course material had been laid along this length. Sections 1 to 19 were laid to the north of the A333 junction, starting 89 m south of the junction with Garnier Road and working southwards. There is a non-experimental length of 398 m between the end of section 19 and the traffic lights. This is considered to be sufficient to allow commercial vehicles to attain their crusing speed before reaching the experimental sections. Sections 20 to 39 were laid from the railway bridge south of the A333 junction working northwards. A non-experimental length of 426 m exists between the end of section 39 and the traffic lights. The work was carried out during the period 26 June to 5 July, 1972.
The road carries a considerable number of heavily loaded container vehicles and this coupled with the warm weather experienced in the south means that this site is subjected to severe conditions regarding defor- mation. Table 2 gives the results of traffic counts carried out on either side of the A333 junction.
TABLE 2
Traff iccounts on A33 Winchester By-pass (Northbound carriageway) (16h count 06.00 to 22.00 increased by 6%)
Date
30/11/71
1/3/72
Site
North of A333 junction (Sections 1-19)
South of A333 junct ion (Sections 20-39)
Lane
Left
Right
Left
Right
Commercial vehicles
2506
314
2031
117
Total vehicles
7857
3543
6543
2486
During the last week in January 1973 and the first week in February axle loads on the nearside lane were measured on the site north and south of the junction with A333 respectively. The frequency/load distribution for the average daily traffic is shown in Fig. 2 where it can be seen that three-quarters of the commercial-vehicle axles weigh less than 5400 kg and that about 0.6 per cent of axles are loaded above the legal limit o f 10 tons.
4. M I X I N G AND LAYING
4.1 Mixing
Mixing was carried out at the Hampshire County Council's asphalt plant at Micheldever, about 20 km from the By-pass. The mixing plant was a Parker Starmix 7. Each experimental mix consisted of 9 batches which were dropped into one lorry giving a total mix of 13.7 t per section. Incremental samples were taken during discharge from the mixing plant f rom alternate batches by a scoop and combined to form a bulk
4
sample of about 10 kg for each lorry load. This was quartered at the mixing plant and one quarter was analysed by the Hampshire County Laboratory. Another quarter was retained for subsequent check analysis by the DOE Materials Testing Laboratory, Stanmore. The means of the analyses are given in Appendix 2. The temperature of the asphalt dropped into the lorry was checked, the mean of five values being taken. Samples of the sands and filler used were removed from the hot bins for grading checks. Mixing generally started at 6.00 a.m. and five lorry loads were mixed and were available at the By-pass before laying commenced. The asphalt was covered with tarpaulins during transport.
4.2 Laying
Laying was carried out using a Blaw-Knox type PF20 paver-finisher. Because of possible difficulties with the richest mixes the leanest mixes were laid first so that any decision regarding rejection of a rich mix could be foreseen from the behaviour of the leaner mixes. On arrival at the site the asphalt lorries were lined up in front of the paver in order of increasing binder contents and laying proceeded continuously as far as possible in order to produce an even riding surface. Since the asphalt was being laid on new base-course material no
tack coat was used.
Before each lorry discharged the asphalt into the hopper of the paver the appearance of the asphalt was noted. The temperature and appearance of the asphalt in the paver hopper and or- the road after the paver were also noted. Temperature measurement was carried out using a thermisto~ tronic thermometer. Five measurements of temperature were taken of the asphalt in the hopper and 5 measurements of temperature at about 20 mm depth were also taken in the asphalt in the wheel track behind the paver prior to rolling. The thickness of the asphalt laid (target 38 + 4 mm) was checked occasionally using a depth probe, but this was not considered to be very accurate due to the presence of irregularities in the base-course surface. A mean thickness for the compacted asphalt was thus calculated using a compacted asphalt density of 2.3 t/m 3 from a knowledge of the tonnage, section length and width (excluding chippings). The performance of the Blaw Knox was noted and, when difficulties were encountered, e.g., severe 'picking up' on the screed and inability to control the thickness of laid asphalt, any richer mix containing the same sand was not laid. On some days to aid continuity 10 sections (i.e., 2 sands) were laid in one lane in the morning and the equivalent 10 sections laid in the adjoining lane in the afternoon. The layout of the sections is given in Fig. 3.
4.3 Chipping
After the asphalt had been laid it was chipped using a Bristowe's chipping spreader. Samples of the chippings were taken for grading and flakiness testing and for percentage coking by the Hot-Sand test. An average failure rate of about 2 per cent was found in the 'Hot-Sand' tests. The target rate of spread was 70 per cent of the total area coverage; this amounted to 11 kg/m 2 (110 yd 2 / ton). Before the work started the rate of spread was checked and the spreader adjusted. Thereafter it was only adjusted when the rate had changed markedly from the target rate. The rate of spread of chippings was determined for each section of material laid using ten trays each 300 mm square laid in echelon on the road in front of the chipping spreader. After the spreader had passed the trays were removed and weighed on a spring balance calibrated in rate of spread.
In every section a strip about 0.5 m long and covering the whole of the width of the left lane was left unchipped. These strips will provide information on the development of texture depth under the action of weathering, traffic and oil droppings. On either side of each strip (except for those in sections containing Croxden sand) and in the nearside wheel track two small areas were chipped at 14.3 kg/m 2 (85 yd2/ton) and 9.3 kg/m 2 (130 yd2/ton). These will provide information on the relationship between texture depth and rate
of embedment.
4.4 Rolling
Before rolling, the temperature of the asphalt was measured in the wheel track, five measurements being taken at a depth of about 20 ram. The asphalt was rolled by two 8t double-wheeled rollers. The work was first rolled by a roller operating at about 5 km/h rolling approximately in strips of ½ roller width per
5
double pass, i.e., about 6 double passes per lane width. Inevitably the middle of the lanes received more roller passes. The first rolling was then followed up by a back-roller operating at about 2 km/h rolling several sections in one pass. All the sections received the same pattern of rolling and the roller was occasionally held off the asphalt if the latter was considered to be too soft during laying. The behaviour of the asphalt during rolling
was noted.
4.5 Appearance of the asphalt after laying
After rolling the work was subjectively rated by appearance, e.g., fatting-up and texture depth. Measure- ments of texture depth were carried out after the completion of the northern half of the laying and again after the remaining asphalts had been laid. Measurements were made in the wheel track, five being made in each section and bothlanes. Tables 3-10 give a summary of all the subjective assessments and quantitive measurements
made.
4.6 Summary of weather conditions during laying work
During ihe period of experimental work the weather was generally cool and overcast and apart from wet weather on 27 June laying conditions were ideal. A diary of specific events that occurred during laying is
included in Appendix 3.
5. INITIAL RESULTS
5.1 Analysis of mixtures laid on A33 Winchester By-pass
Appendix 2 gives tables of the analysis results of all the mixtures laid. Apart from the left-hand-lane sections incorporating Chertsey sand, the stone contents were well within 30 + 5 per cent. The fdler:sand ratio (target 1:6, i.e., 16.7%) varied from 14.3% to 22.7% but was generally near the target value. The target stone content for the Chertsey sand sections in the left-hand lane was 38% because of the proportion of > 2.36 m m (Mesh No. 7) present in the sand. The target.was reduced to 30% stone for the right-hand lane
sections.
5.2 Summary of observations and measurements
Tables 3-10 summarise the measurements and assessments made on all the experimental sections. In general, asphalt delivery and rolling temperatures were within normal recommended limits, but tended to be near the 'high' end. The calculated laid thicknesses varied from 29 to 58 mm but the majority were within the target range of 38 + 4 ram. There was a tendency for more results to be higher than the target range rather than lower. In general, for a particular sand the lower the binder content the greater was the thickness. The thinnest sections were those having the highest binder contents when the paver-finisher could no longer effectively control the laid thickness. Where the rolling condition of the asphalt is described as 'soft ' in Tables 3-10 there was up to about 5 cm of longitudinal movement of the asphalt during rolling. The rate of spread of chippings was fairly constant (average 11.7 kg/m 2) and close to the target value of 11 kg/m 2 and the initial texture depths did not show great differences between rich and dry sections.
As far as mixing and laying of these materials are concerned it is possible to define limits beyond which the mixtures were either excessively dry or too rich to lay satisfactorily. The 'opt imum' mixtures laid by subjective assessment of appearance and workability can also be defined. These may or may not correspond with the opt imum based on long-term performance. Table 11 gives these subjectively assessed values for the "acceptable' range of binder contents for the sands and also the observed subjective 'opt imum' binder content. These results are recorded for comparison with the long-term performance of the asphalt.
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TABLE 11
'Acceptable' ranges and 'optimum' binder contents (subjectively assessed)
Binder content % Sand
'Acceptable' range 'Observed optimum' Target optimum
Croxden
Fairoak
Hilton
Rockbeare
Chertsey
Durham
Redhill
Mersey
8.2 - 11.0
8.0 - 9.8
6.0 - 7.9
8 . 3 - 10.7
5.5 - 7.9
6.O - 8.1
5.6 - 8.1
5.8 - 7.7
9.5
8.9
7.0
8.4
6.7
7.1
7.1
7.0
9.9
8.7
6.4
9.4
5.9
6.5
7.2
7.4
NOTES: 1. 'Acceptable' means that the asphalt could be laid satisfactorily, but that the extremes may be considered to be dry or rich in appearance.
2. 'Observed optimum' means that the asphalt before and after being laid and compacted appeared neither rich nor dry and that its workability was normal. It was difficult to assess the observed optimum value to better than + 0.5 per cent binder.
3. The target optimum values are those obtained during the Marshall tests; the laboratory work to derive these values will be described elsewhere.
6. FUTURE w o R K
The experimental sections will be assessed by the following measurements at regular intervals:
(a) The transverse profde
(b) Sideway force coefficients at 50 and 80 km/h
(c) Texture depth.
The Panel for the Inspection of Full-Scale Road Experiments will assess the overall condition of the surfacings
visually from time to time.
7. ACKNOWLEDGEMENTS
The site was made available by the South Eastern Regional Controller. The co-operation of the Hampshire County Survey, Mr. H.N. Jenner, and his staff, in particular Mr. C.A. Veysey, Assistant County Surveyor,
15
is gratefully acknowledged. The work was planned and directed by A Please and F A Jacobs and the research team included Messrs P Green, D Grinter, D R Hanger, N Unahabhokka, M Lush, G Slade, E W H Spry and D White. The work described in this Report was carried out in the Materials Division of the Highways Department of the Transport and Road Research Laboratory (Division Head, G F Salt).
8. REFERENCE
1. DEPARTMENT OF THE ENVIRONMENT, ROAD RESEARCH LABORATORY. Road Research 1971. Annual Report of the Road Research Laboratory. London, 1972 (HM Stationery Office).
16
9. APPENDIX 1
SANDS USED FOR THE FULL-SCALE EXPERIMENT ON A33 WINCHESTER BY-PASS
1. Croxden fine sand from Croxden Gravel Ltd., Croxden Common, Cheadle, STOKE-ON-TRENT.
Sub-angular quartz with muscovite, haematite and clay particles; reddish-brown in colour.
2. Fairoak sand from Harleyford Aggregates Ltd., Stubblington Farm House, Fair Oak, Nr. Eastleigh, HANTS.
Mainly iron-stained angular quartz with some chert, yellowish-brown in colour.
3. Hillton sand from
Supplied by:
Hilton Gravel Ltd., Stoke-on-Trent, STAFFS.
Blue Circle Aggregates Ltd., Rugeley Road, Hednesford, STAFFS.
Rounded quartz with inclusions, iron-staining and detritus; dark pinkish brown variegated in colour.
4. Rockbeare sand from
.
E C C Quarries Ltd., Rockbeare Pit, Nr Ottery St Mary, DEVON.
Quartzite, quartzitic sandstone and quartz light pinkish-brown in colour.
Uncrushed Chertsey sand from Hall Aggregate (Thames Valley) Ltd., Staines Lane, Chertsey, SURREY.
Sub-rounded chert with quartz and flint; medium brown variegated in colour.
6. Durham sand from Sherburn Hill Quarry,
Supplied by: Hargreaves Quarry Ltd., Houghton Road, Hetton-le-Hole, CO. DURHAM
Sandstone, grit and quartz; light-brown in colour.
17
7. Redhill 65 sand from British Industrial Sand Ltd., Hohnethorpe, Redhill, SURREY.
Sub-rounded quartz; white in colour.
8. Washed Mersey sand from Hoveringham Dredging Ltd., South Herculaneum Dock, LIVERPOOL.
Dredged river sand; mainly rounded quartz with detritus and shell fragments, dull-brown in colour speckled with white shell.
18
10. APPENDIX 2
COMPOSITION OF MIXTURES LAID ON A33 WINCHESTER BY-PASS Analysis results (means of 2 analyses)
TABLE 1
Croxden Sand
Section
4
4
Lane
Left
Right
Left
Right
Left
Right
Left
Right
Left
Right
Composition by weight (%)
Filler/ Corrected'- Stone Sand Filler Binder
sand binder
30.1 51.8 9.6 18.5 8.5 8.5
29.2 53.8 8.7 16.2 8.3 8.2
26.2 54.3 9.6 17.7 9.9 9.5
29.6 52.1 9.1 17.5 9.2 9.2
26.4 53.3 t0.0 18.8 10.5 10.1
28.9 51.7 9.4 18.2 10.0 9.9
27.7 52.6 9.3 17.7 10.4 10.2
29.5 50.5 9.3 18.4 10.7 10.6
29.4 50.8 8.7 17.1 11.1 11.0
31.4 48.5 8.8 18.1 11.3 11.4
NOTE to Tables 1 to 8 of Appendix 2. Hants C.C. used 'bottle ' method (BS 598:1958 Method C); DOE Materials Testing Laboratory, Stanmore used 'sieve-shaker' method (BS 598 :1958 Method D); both sets of results were corrected to 'dry-sieving' basis.
19
TABLE 2
Fairoak Sand
Section Lane Composition by weight (%)
Stone Sand Filler Filler/ Binder Corrected sand binder
6 Left 32.0 51.6 8.3 16.1 8.1 8..3
6 Right 26.3 58.9 8.4 14.3 8.4 8.0
7 Left 30.9 52.0 8.3 16.0 8.8 8.9
7 Right 31.5 52.0 7.9 15.2 8.6 8.8
8 Left 31.0 51.6 7.7 14.9 9.7 9.8
8 Right 30.4 51.8 8.1 15.6 9.7 9.7
9 Left 29.2 52.0 8.3 16.0 10.5 10.4
9 Right 32.5 49.8 7.7 15.5 10.0 10.2
TABLE 3
Hilton Sand
Section Lane
Composition by weight (%)
Stone Sand Filler Filler/ Binder Corrected sand binder
10 Left 29.5 54.2 10.2 18.8 6.1 6.0
10 Right 32.5 52.2 9.6 18.4 5.7 6.0
11 Left 30.4 52.8 9.7 18.4 7.1 7.1
11 Right 29.4 54.8 8.9 16.2 6.9 6.8
12 Left 31.6 51.4 9.3 18.1 7.7 7.9
12 Right 30.1 52.9 9.6 18.1 7.4 7.4
13 Left 31.7 51.6 9.6 18.6 8.1 8.3
13 Right 29.2 53.2 9.4 17.7 8.2 8.1
14 Left 31.4 50.8 8.9 17.5 8.9 9.0
14 Right 29.2 52.3 9.5 18.2 9.0 8.9
2 0
TABLE 4
Rockbeare Sand
Section Lane
15 Left
Composition by weight (%)
Stone Sand Filler Filler/ Binder Corrected sand binder
30.7 50.5 10.0 19.8 8.8 8.9
28.1 50.7 11.5 22.7 9.7 9.5 15
16
16
Right
Left
Right
31.6 48.1 10.6 22.0 9.7 9.9
30.0 49.7 10.1 20.3 10.2 10.2
17 Left 27.2 51.3 . 10.5 20.5 11.0 10.7
17 Right 30.2 49.2 10.2 20.7 10.4 10.4
18 Left 30.4 48.3 10.1 20.9 11.2 11.2
18 Right 29.2 49.2 10.1 20.5 11.5 11.4
19 Left 32.4 49.2 10.3 20.9 8.1 8.3
19 Right 33.1 49.2 9.6 19.5 8.1 8.4
TABLE 5
Chertsey Sand
Composition by weight (%) Section Lane
Stone Sand Filler Filler/ Binder Corrected sand binder
20 Left* 38.8 48.6 8.1 16.7 4.5 4.6**
20 Right 31.9 55.0 8.1 14.7 5.0 5.2
21 Left* 36.8 49.4 8.2 16.6 5.6 5.5**
21 Right 31.7 54.6 8.8 16.1 5.9 6.1
22 Left* 37.1 48.6 7.9 16.3 6.4 6.3**
22 Right 33.4 51.9 8.3 16.0 6.4 6.7
23 Left* 48.0 37.2 8.2 22.0 6.6 7.6**
23 Right 32.6 52.5 7.8 14.9 7.1 7.4
24 Left* 38.5 46.4 7.7 16.6 7.4 7.5 * *
24 Right 31.2 53.0 8.0 15.1 7.8 7.9
target stone content 38% owing to 15% retained on 2.36 mm (Mesh 7) sieve of Chertsey sand. Target reduced to 30% for right-lane section.
corrected to 38% stone content.
21
TABLE 6
Durham Sand
Section Lane
Composition by weight (%)
Stone Sand Filler Binder
25 Left 28.9 55.5 9.3 16.8 6.3 6.2
25 Right 32.4 52.8 9.0 17.0 5.8 6.0
26 Left 29.0 54.9 8.9 16.2 7.2 7.1
26 Right 30.3 52.7 10.3 19.5 6.7 6.7
27 Left 30.7 52.4 9.2 17.6 7.7 7.8
27 Right 30.4 51.8 10.2 19.7 7.6 7.6
28 Left 31.3 51.0 9.2 18.0 8.5 8.6
28 Right 31.9 50.2 10.0 19.9 7.9 8.1
29 Left 34.8 47.9 8.7 18.2 8.6 9.1
29 Right 31.6 49.1 10.3 21.0 9.0 9.2
Filler/ Corrected sand binder
TABLE 7
Redhill Sand
Section
30
30
31
31
Lane
Left
Right
Left
Right
32 Left
32 Right
33
33
34
34
Left
Right
Left
Right
Composition by weight (%)
Filler/ Corrected Stone Sand Filler Binder sand binder
33.2 53.1 8.0 15.1 5.7 6.0
28.9 56.8 8.6 15.1 5.7 5.6
31.5 54.1 8.0 14.8 6.4 6.6
30.1 54.3 9.0 16.6 6.6 6.6
31.7 52.9 8.0 15.1 7.4 7.6
30.1 53.6 8.8 16.4 7.5 7.5
29.6 54.6 7.9 14.5 7.9 7.9
30.2 53.5 8.2 15.3 8.1 8.1
32.4 51.1 8.0 15.7 8.5 8.7
30.7 52.0 8.4 16.2 8.9 9.0
22
TABLE 8
Mersey Sand
Composition by weight (%)
Section Lane Filler/ Corrected
Stone Sand Filler Binder sand binder
35 Left 35.2 51.9 7.6 14.6 5.3 5.8
35 Right 30.2 55.7 8.4 15.1 5.7 5.8
36 Left 31.1 54.0 8.5 15.7 6.4 6.5
36 Right 27.9 57.1 8.2 14.4 6.8 6.6
37 Left 30.0 54.9 8.1 14.8 7.0 7.0
37 Right 29.7 54.9 8.2 14.9 7.2 7.2
38 Left 29.2 55.1 8.1 14.7 7.6 7.5
38 Right 29.8 54.2 8.3 15.3 7.7 7.7
39 Left Non-experimental
39 Right 31.5 51.8 7.8 15.1 8.9 9.1
23
11. APPENDIX3
DIARY OF EVENTS
26 June 1972
Sections 1 to 5 (Croxden Sand) starting with the leanest mixture were laid in the morning in the right-lane and the same mixtures laid in the left-lane during the afternoon. The weather remained overcast, cool and dry with a light breeze. Experimental work finished at 16.00 and non-experimental asphalt was laid from Section 1 to Gamier Road junction. The road was opened to traffic at 17.30.
27 June 1972
Sections 6 to 9 (Fairoak Sand) were laid in the morning (both lanes) the right lane being laid first. The richest planned load was not laid because the next leanest mixture, that on Section 9 was considered to be virtually unlayable. The beginning of Section 6 right lane was rolled using a vibrating roller to attempt to flatten a slight bump. This was carried out after Section 9 had been laid in the right lane. The weather started as overcast, cool with a light breeze. As work proceeded it began to rain, becoming heavy later. The left lane was laid on a wet road surface and it was subsequently noted that there was no adhesion between the asphalt and the road. Laying finished at 12.30 and the road was opened to traffic at 13.15.
28 June 1972
In the morning, Sections 10 to 14 (Hilton Sand) were laid (both lanes), the right lane being laid first. In the afternoon Sections 15 to 19 (Rockbeare Sand) were laid-(both lanes), the left lane being laid first. Because the 4th mix (Section 18 left lane) was very rich it was decided at the mixing plant to omit the 5th richest mix and substitute a mix leaner than the 1st (Section 15). The same procedure was adopted for the right lane. A patch at the end of Section 18 (left lane) was removed owing to excessive thickness and replaced. This end of Section 18 was thus subjected to excessive rolling. There was thus some delay before the roller could roll Section 19. The day started with a cloudless sky, cool initially but in the after- noon it became very warm with summer clouds. Laying finished at 17.35 and the road was opened to
traffic at about 18.30.
29 June 1972
No experimental material was laid this day but the road was closed and non-experimental material laid from the end of Section 19 to the traffic lights on the A333 Junction. Measurements, of texture depth were carried out on Sections 1 to 19. The road was re-opened at about 18.30.
30 June to 2 July 1972
No laying was carried out during this period hence the road rehaained open until 07.30, 3 July. The weather on 30 June was warm and sunny and on 1 July was fine and cooler, but on 2 July it rained all day.
3 July 1972
Laying commenced on the north side of the railway bridge about 1.5 km south of the traffic lights at the A333 junction working northwards. In the morning sections 20 to 24 (Chertsey Sand) were laid in the left lane followed by Sections 25 to 29 (Durham Sand) also in the left lane. The afternoon work was similar, laid in the right lane. A section of non-experimental material was then laid after Section 29 (right lane) in an attempt to level up the ends of the sections. The weather remained overcast and cool with some light drizzle in the morning. Laying finished at 17.35 and the road was opened at about 18.30.
24
4 July 1972
No experimental material was laid this day. The weather remained dull but fine. The road was closed owing to bridge works north of Garnier Road.
5 July 1972
In the morning Sections 30 to 34 (Redhill Sand) were laid in the right lane followed by Sections 35 to 39 (Mersey Sand) also laid in the right lane. Work was similar for the left lane in the afternoon except that Section 39 was not laid as the same section laid in the right lane was considered unlayable. Non-experimental material was thus laid up to the end of Section 39 of the right lane. Laying ended at 16.30 and the road was opened at about 18.00. The weather was overcast, cool and dry with a light breeze.
25
Site of exper iment
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Fig. 2. A33 WINCHESTER BY-PASS : AVERAGE DALLY AXLE LOAD DISTRIBUTION ON NEARSIDE LANE OF NORTHBOUND CARRIAGEWAY
(SURVEY CARRIED OUTFROM 2/./1/73 TO 7/2/73)
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P R I N T E D IN E N G L A N D
~( C, °
ABSTRACT
The design of rolled asphalt: a full-scale experiment on A33 Winchester By-pass 1972: M.E. DAINES: Department of the Environment, TRRL Supplementary Report SR 22 UC: Crowthorne, 1974 (Transport and Road Research Laboratory). The laying of rolled asphalt designed using the Marshall Test in a full-scale experiment on the A33 Winchester By-pass, 1972, is described. Eight sands covering a wide range of grading, particle shape, optimum Marshall Stability and optimum binder content (some being outside the grading limits of BS 594: 1961) were used to produce 30% stone-content rolled asphalt wearing courses. Asphalt for each sand was laid with five binder contents; optimum, optimum + 0.75 per cent, and optimum + 1.5 per cent. The experimental sections will be studied by measurements of transverse profile, sideway force coefficient and texture depth.
ABSTRACT
The design of rolled asphalt: a full-scale experiment on A33 Winchester By-pass 1972: M.E. DAINES: Department of the Environment, TRRL Supplementary Report SR 22 UC: Crowthorne, 1974 (Transport and Road Research Laboratory). The laying of rolled asphalt designed using the Marshall Test in a full-scale experiment on the A33 Winchester By-pass, 1972, is described. Eight sands covering a wide range of grading, particle shape, optimum Marshall Stability and optimum binder content (some being outside the grading limits of BS 594: 1961) were used to produce 30% stone-content rolled asphalt wearing courses. Asphalt for each sand was laid with five binder contents; optimum, optimum + 0.75 per cent, and optimum + 1.5 per cent. The experimental sections will be studied by measurements of transverse proftle, sideway force coefficient and texture depth.
