1. What is Ultra‑Thin Wearing Course
The NovaChip system consists of two key components: a modified emulsified asphalt waterproof bonding layer, and gap‑graded skeleton‑structure hot‑mix modified asphalt mixture. The finished overlay thickness is merely 1‑2 cm.
NovaChip ultra‑thin wearing course places 10‑20 mm gap‑graded hot modified asphalt mixture directly atop a modified emulsified asphalt film. Specialized paving equipment performs synchronous operations: spraying the modified emulsified asphalt waterproof bonding layer and paving gap‑graded hot mixture in one pass. Final compaction by rollers completes the whole construction in a single forming process.
2. Material Technical Requirements
2.1 Modified Emulsified Asphalt for Bonding Layer
The modified emulsified asphalt waterproof tack coat features fast breaking speed, delivering superior bonding strength between the existing pavement and ultra‑thin overlay, while performing waterproofing functions. The typical application rate ranges from 0.6‑1.2 kg/m². The actual spraying dosage shall be adjusted according to mixture volumetric properties and on‑site pavement conditions.
|
Test Item
|
Unit
|
Technical Requirement
|
Test Method
|
|
Breaking Speed
|
—
|
Rapid‑setting
|
T0658
|
|
Particle Charge
|
—
|
Cationic (+)
|
T0653
|
|
Sieve residue (1.18 mm sieve), max
|
%
|
0.1
|
T0652
|
|
Saybolt Viscosity (50 ℃)
|
s
|
10‑70
|
T0623
|
|
Evaporation Residue Content, min
|
%
|
62
|
T0651
|
|
Penetration (25 ℃,100 g,5 s)
|
0.1 mm
|
60‑150
|
T0604
|
|
Ductility (5 ℃), min
|
cm
|
40
|
T0605
|
|
Solubility (trichloroethylene), min
|
%
|
96.5
|
T0607
|
|
Elastic Recovery (25 ℃), min
|
%
|
60
|
T0662
|
|
Storage Stability‑1‑day, max
|
%
|
1
|
T0655
|
|
Storage Stability‑5‑day, max
|
%
|
5
|
T0655
|
2.2 Modified Asphalt Binder
Modified asphalt binder shall be custom‑formulated based on geographic location, local climate, traffic volume and vehicle speed. It delivers high cohesion and anti‑aging performance, complying with Technical Specifications for Construction of Highway Asphalt Pavements (JTG F40‑2004) and SUPERPAVE binder specifications.
|
Test Item
|
Unit
|
Technical Requirement
|
Test Method
|
|
Penetration (25 ℃,5 s,100 g), min
|
0.1 mm
|
50
|
T0604
|
|
Ductility (5 ℃, 5 cm/min), min
|
cm
|
30
|
T0605
|
|
Softening Point TR&B, min
|
℃
|
75
|
T0606
|
|
Kinematic Viscosity (135 ℃), max
|
Pa·s
|
3
|
T0620
|
|
Flash Point, min
|
℃
|
230
|
T0611
|
|
Solubility (trichloroethylene), min
|
%
|
99
|
T0607
|
|
Separation‑48‑h softening‑point difference, max
|
℃
|
2.5
|
T0661
|
|
Elastic Recovery (25 ℃), min
|
%
|
80
|
T0662
|
|
RTFOT Residue‑Mass Loss
|
%
|
±1.0
|
T0609
|
|
RTFOT Residue‑Penetration Ratio (25 ℃), min
|
%
|
60
|
T0604
|
|
RTFOT Residue‑Residual Ductility (5 ℃), min
|
cm
|
20
|
T0605
|
2.3 Gap‑Graded Skeleton Void Hot‑Mix Asphalt Mixture
The gap‑graded skeleton‑void structure provides adequate rising space for breaking emulsified asphalt and ensures strong interlayer bonding with the overlay mixture. Instead of conventional mix‑design procedures, a volumetric‑based mix design combined with asphalt film‑thickness evaluation is adopted to enhance mixture durability.
2.3.1 Coarse Aggregate
|
Test Item
|
Unit
|
Requirement
|
Test Method
|
|
Apparent Specific Density, min
|
t/m³
|
2.60
|
T0304
|
|
Water Absorption, max
|
%
|
2
|
T0304
|
|
Crushing Value, max
|
%
|
25
|
T0316
|
|
Los Angeles Abrasion Loss, max
|
%
|
28
|
T0317
|
|
Soundness, max
|
%
|
12
|
T0314
|
|
Polished Stone Value PSV, min
|
PSV
|
40
|
T0321
|
|
Flat‑elongated Particle Content (Total), max
|
%
|
13
|
T0312
|
|
Flat‑elongated (>9.5 mm), max
|
%
|
10
|
T0312
|
|
Flat‑elongated (<9.5 mm), max
|
%
|
15
|
T0312
|
|
<0.075 mm passing (washing method), max
|
%
|
1
|
T0310
|
|
Soft‑rock Content, max
|
%
|
3
|
T0320
|
|
Asphalt Adhesion Grade, min
|
Grade
|
5
|
T0616
|
Coarse Aggregate Gradation Specification
|
Nominal Size (mm)
|
Passing Percentage by Mass (%)
|
|
|
|
|
|
|
15.0 mm
|
11.4 mm
|
8.0 mm
|
5.6 mm
|
2.36 mm
|
|
11.4‑16
|
100
|
0‑20
|
—
|
—
|
—
|
|
8‑11.4
|
100
|
85‑100
|
0‑20
|
0‑5
|
—
|
|
5.6‑8
|
—
|
100
|
90‑100
|
0‑15
|
0‑5
|
2.3.2 Fine Aggregate
|
Test Item
|
Unit
|
Requirement
|
Test Method
|
|
Apparent Density, min
|
t/m³
|
2.50
|
T0328
|
|
Soundness (>0.3 mm fraction), min
|
%
|
12
|
T0340
|
|
Clay Content (<0.075 mm), max
|
%
|
3
|
T0333
|
|
Sand Equivalent, min
|
%
|
60
|
T0334
|
|
Methylene‑Blue Value, max
|
g/kg
|
25
|
T0349
|
|
Angularity (Flow Time), min
|
s
|
30
|
T0345
|
2.3.3 Mineral Filler
|
Test Item
|
Unit
|
Requirement
|
Test Method
|
|
Apparent Density, min
|
t/m³
|
2.50
|
T0352
|
|
Moisture Content, max
|
%
|
1
|
T0103
|
|
Gradation <0.6 mm
|
%
|
100
|
T0351
|
|
Gradation <0.15 mm
|
%
|
90‑100
|
T0351
|
|
Gradation <0.075 mm
|
%
|
80‑100
|
T0351
|
|
Appearance
|
—
|
No agglomerates
|
Visual
|
|
Hydrophilic Coefficient
|
—
|
<1
|
T0353
|
|
Plasticity Index
|
—
|
<4
|
T0354
|
|
Heating Stability
|
—
|
Record actual observation
|
T0355
|
2.3.4 NovaChip Mixture Aggregate Gradation Range
|
Sieve Size (mm)
|
16
|
13.2
|
9.5
|
4.75
|
2.36
|
1.18
|
0.6
|
0.3
|
0.15
|
0.075
|
Asphalt Content (%)
|
|
Passing Mass %
|
100
|
85‑100
|
60‑80
|
25‑35
|
23‑30
|
12‑22
|
8‑16
|
6‑12
|
5‑10
|
4‑7
|
4.6‑5.6
|
2.3.5 Mixture Mix‑Design Requirements
|
Test Item
|
Unit
|
Standard
|
|
Marshall Compaction (double‑sided)
|
blows
|
75
|
|
Specimen Dimension
|
mm
|
Φ101.6 × 63.5
|
|
Air Voids VV
|
%
|
8‑12
|
|
Voids in Mineral Aggregate VMA, min
|
%
|
20
|
|
Marshall Stability MS, min
|
kN
|
6
|
Note: Wax‑sealing method shall be adopted for measuring bulk specific gravity of NovaChip mixture specimens.
2.3.6 Performance Verification for Mixture Design
|
Test Item
|
Unit
|
Standard
|
Test Method
|
|
Surface Texture Depth, max
|
mm
|
1.0
|
T0731
|
|
Wheel‑Tracking Dynamic Stability, min
|
cycles/mm
|
3000
|
T0719
|
|
Asphalt Drain‑down Test, min
|
%
|
0.1
|
T0732
|
|
Water Stability‑Residual Marshall Stability, min
|
%
|
80
|
T0709
|
|
Water Stability‑Freeze‑Thaw Split TSR, min
|
%
|
80
|
T0729
|
3. Construction Procedure
3.1 Pre‑Construction Preparation
-
Existing Pavement Treatment: Repair underlying pavement layers to restore cross‑slope, longitudinal slope and flatness. Ensure pavement structural integrity and sufficient bearing capacity.
-
Pavement Cleaning: Conduct rough sweeping first. Use mechanical sweepers plus manual labor to clear dust and debris from pavement surface and cracks. For surfaces milled by fine milling machines, special sweeping equipment is required. Manual detailed cleaning shall be completed along road edges. Blowers shall remove fine dust inside cracks.
-
Construction Equipment List: 1 set of NovaChip ultra‑thin paver; 2 sets of 10‑12 t double‑steel‑wheel rollers; 1 small‑size roller; 2 water tank trucks (>8 t); 1 road dust‑removal unit; 1 small cutting machine; 2 emulsified asphalt tank trucks.
3.2 Hot‑Mix Mixture Production
-
Asphalt Plant Calibration: Calibrate weighing & metering systems; inspect and lubricate transmission components; overhaul dust‑removal systems. Install screen meshes of 3.0 mm, 6 mm, 12 mm and 19 mm for hot‑material bins.
-
Adjust Production Mix Ratio:
-
Sample stockpile aggregates for sieve analysis (water‑sieving). Tune cold‑feed proportions, feeder rotating speed, vibration amplitude and gate opening angle to match target gradation.
-
Feed aggregates according to adjusted cold‑feed parameters.
-
Collect samples from hot bins when aggregate temperature stabilizes between 180‑190 ℃. Perform water‑sieving test and fine‑tune hot‑bin discharge ratios.
-
Determine volumetric properties and optimum asphalt content by specimens compacted 100 times by gyratory compactor (or 50 blows each side Marshall compaction).
-
Production Temperature Requirements:
-
Aggregate heating temperature: 180‑190 ℃
-
Modified asphalt heating temperature: 165‑175 ℃
-
Mixing temperature: 170‑180 ℃
-
Effective mixing duration: 30‑45 seconds
3.3 Mixture Transportation
Use dump trucks ≥15‑ton capacity. Coat inner floor and side panels with anti‑adhesive agent. Cover truck loads to prevent rapid heat loss. Check truck floor height to match paver feeding requirement.
3.4 Paving Work
-
Spray modified emulsified asphalt at 60‑80 ℃. Adopt precise metering to achieve uniform application.
-
Theoretical tack‑coat dosage: 0.6‑1.2 kg/m². Field engineers adjust value for actual site pavement conditions.
-
Hot‑mix asphalt mixture paving temperature: 150‑170 ℃. Place hot mixture directly over fresh sprayed emulsified asphalt film. Heated vibrating screed performs finishing.
3.5 Compaction & Rolling
-
Deploy at minimum one 10‑12 t steel‑wheel roller (plus standby roller). Complete 2 static‑compaction passes.
-
Perform rolling when mixture temperature remains above 140 ℃. Apply static pressure only. Vibration rolling and rubber‑tyre rollers are forbidden.
-
Rolling objective: achieve interlocking aggregate re‑positioning rather than pursuing extreme compaction degree.
-
Equip rollers with soap‑water anti‑stick spraying system and scrapers to prevent hot‑mixture adhesion on steel drums.
3.6 Traffic Opening
-
Traffic may reopen after pavement surface temperature falls below 50 ℃.
-
Under ambient temperature of 25 ℃, traffic can be reopened within 20‑40 minutes.
3.7 Quality Control
3.7.1 On‑Site Construction Control
-
Finished mixture shall be homogeneous; no pale aggregates, no segregation, no clumping.
-
Strictly control paving thickness to avoid segregation; closely monitor paving and compaction temperatures.
-
Execute longitudinal joint overlapping specifications for tightness and smoothness.
3.7.2 Acceptance Criteria
|
Inspection Item
|
Quality Requirement
|
Testing Frequency
|
Test Method
|
|
Surface Appearance
|
Smooth & uniform surface; no looseness, pale aggregates, wheel marks or scratches
|
Full‑length continuous
|
Visual inspection
|
|
Transverse Joint
|
Tight, smooth, straight, no bumping at crossing
|
Each joint
|
Visual inspection
|
|
Longitudinal Joint
|
Overlap width ＜80 mm; unevenness＜6 mm
|
Full‑length continuous
|
Visual / 3‑m straightedge measurement
|
|
Edge Alignment
|
Horizontal deviation ≤ ±50 mm within any 30 m segment
|
Full‑length continuous
|
Visual / tape measure
|
|
Skid Resistance‑Transverse Force Coefficient, min
|
45
|
Full‑length continuous
|
T0965
|
|
Surface Texture Depth TD, min
|
1 mm
|
5 points per km
|
T0961
|
4. Core Performance Advantages
-
Fast Traffic Re‑Opening: High construction output. Night‑time construction is feasible, extending annual working window. Traffic can resume within as short as 40 minutes after paving.
-
Enhanced Road Safety: Texture depth＞0.8 mm, British Pendulum Number＞55. Gap‑graded skeleton improves tire adhesion on wet pavements, reducing side‑slip risk. It suppresses hydraulic water‑film and tire spray under rain conditions, delivering surface drainage capability.
-
Noise Reduction: Special skeleton‑void texture lowers traffic noise by 2‑3 dB(A) compared with dense‑graded asphalt surfaces, improving driving comfort.
-
Excellent Waterproofing: High‑rate modified emulsified asphalt tack coat delivers powerful interlayer bonding and prevents surface water infiltration. It seals fine existing cracks on original pavement.
-
Extended Service Life: The 2 cm high‑performance overlay boosts resistance against heavy traffic load, aging and permanent deformation. Under proper construction, service life is generally no less than 5 years; international projects achieve up to 10‑year service life.
5. Performance Comparison: NovaChip Ultra‑Thin Wearing Course vs Microsurfacing
|
Comparison Item
|
NovaChip Ultra‑Thin Wearing Course
|
Microsurfacing
|
Remarks
|
|
Noise Level
|
Low
|
High
|
|
|
Surface Appearance
|
Excellent
|
Fair‑poor
|
|
|
Anti‑Skid Performance
|
Good, minimal performance decay
|
Moderate, obvious decay over time
|
|
|
Functional Rehabilitation
|
Yes
|
No
|
|
|
Traffic Safety
|
High
|
Moderate
|
NovaChip reduces tire spray in rain
|
|
Water‑Sealing Capacity
|
High
|
High
|
|
|
Service Life (proper construction)
|
6‑8 years
|
3‑4 years
|
|
6. Project Cost
NovaChip Ultra‑Thin Wearing Course: USD 7.0‑8.5 per square meter (50‑60 RMB/m²)
Published by Henan Highway Guardian Transportation Technology Co., Ltd. Document Date: Oct 10, 2026
