Asphalt Pavement Defects Caused by Paver Operations

Understanding Asphalt Pavement Defects Caused by Paver Operations: Insights from IRC Guidelines

Published on October 26, 2025, 06:56 PM IST

Asphalt pavements are critical infrastructure components in road construction, providing smooth, durable surfaces for vehicular traffic. However, defects arising from improper paver operations can significantly compromise pavement longevity and performance. This article delves into common defects such as low density/poor compaction, tearing or scuffing, and inconsistent mat thickness, drawing from practical observations and integrating key guidelines from the Indian Roads Congress (IRC). By examining causes, results, remedies, and specific numerical requirements, we aim to equip engineers and contractors with actionable insights for high-quality asphalt laying.

Introduction to Paver-Induced Defects in Asphalt Pavements

Paver speed and operational parameters directly influence the uniformity, smoothness, and compaction of the asphalt mat. In road construction, inappropriate paver actions can lead to three primary defects: excessive paver speed, inconsistent speed, and frequent stoppages. These issues manifest as surface irregularities, poor density, and reduced structural integrity, ultimately accelerating deterioration.

According to IRC guidelines, achieving optimal compaction is paramount, with minimum density targets ensuring the pavement withstands traffic loads. The IRC:111-2009 specifies that dense graded bituminous mixes must be laid using mechanized pavers to maintain consistency, while IRC:105-2019 emphasizes high-quality hot mix asphalt production for airfield and highway applications.730 Proper adherence to these standards can mitigate defects and extend service life.

Defect 1: Low Density / Poor Compaction Behind the Screed

Causes

• Improper pre-compaction by the screed, resulting in inadequate initial densification.
• Poor mix consistency or excessive paver speed, leading to uneven material distribution and air voids.

Results

Weak pavement with high air voids, prone to early deterioration under traffic loads, including raveling, cracking, and water ingress.

Remedies

• Ensure the mix is within specifications (IRC:111-2009 requires mineral aggregates meeting IS:383 standards and bituminous binders per climatic zones).32
• Optimize paver speed and screed pressure; maintain steady operation to avoid segregation.
• Monitor temperature: Hot mix should be transported in insulated vehicles and laid at 140–160°C for optimal workability (IRC:105-2019).7

Key IRC Data

IRC standards mandate a minimum compaction density of 98% of laboratory maximum dry density for bituminous layers to prevent premature failure (IRC:105-2019 for airfield pavements; similar for highways per IRC:37-2018).4042 Field density tests (e.g., core samples) must confirm this, with air voids limited to 3–5% for dense-graded mixes (IRC:111-2009).40

Defect 2: Tearing or Scuffing of the Mat

Causes

• Cold mix (below 130°C), reducing binder fluidity.
• Incorrect screed angle of attack or sudden starts/stops, causing shear forces on the mat.

Results

Surface irregularities, open texture, and poor compaction, leading to reduced skid resistance and accelerated wear.

Remedies

• Maintain mix temperature at 150–170°C during laying (IRC:111-2009).32
• Adjust screed settings: Set correct depth, angle (typically 3–5°), crown, and check for wear/build-up on the plate.
• Avoid abrupt speed changes; coordinate with haul trucks for continuous supply.

Key IRC Data

For dense bituminous macadam (DBM) and bituminous concrete (BC), IRC:111-2009 requires Marshall stability ≥9 kN for BC and ≥8 kN for DBM, with flow values of 2–4 mm to ensure resistance to deformation.40 Pavers must lay to a minimum width of 7.5 m, with no visible defects like tearing post-compaction (IRC:105-2019).7

Defect 3: Inconsistent Mat Thickness

Causes

• Screed depth/angle not properly set or paver speed mismatched to material supply.
• Supply changes or stoppages, forcing speed adjustments and uneven deposition.

Results

Variations in thickness across width or longitudinally; thin spots appear depressed, thick spots raised, leading to uneven ride quality and stress concentrations.

Remedies

• Maintain steady paver speed matching mix supply; use hopper/feeders for uniform feed.
• Calibrate screed regularly; ensure longitudinal and transverse evenness within ±6 mm (IRC:SP:16-2004).6
• Coordinate trucks to prevent starvation or overload; monitor for thermal differentials.

Key IRC Data

Some Common Paving Speeds (Adapted from Top Quality Paving Guidelines, Aligned with IRC:111-2009)

Mat Thickness	Rate from Plant (tph)	Ideal Paving Speed (fpm)
2 inches	120	15
2 inches	170	20
2 inches	210	25
2 inches	250	30
3 inches	290	35
3 inches	190	15
3 inches	315	25
4 inches	160	10
4 inches	250	15
4 inches (12 ft lane)	335	20

These speeds ensure compatibility with compaction trains, assuming a 12 ft lane width (IRC:37-2018 recommends minimum lift thickness of 3 times nominal maximum aggregate size, e.g., ≥50 mm for 19 mm NMAS).1012

Key Paver Operation Aspects to Focus On

• Maintain Steady Paver Speed: Match to mix supply and rollers; avoid exceeding 30 fpm for thick lifts.
• Ensure Hopper/Feeder Adjustment: For uniform feed, preventing segregation (IRC:111-2009 mandates anti-stripping agents if tensile strength <80%).32
• Calibrate Screed: Correct depth, 3–5° angle, crown for drainage; inspect for wear.
• Avoid Cold Joints/Material Unevenness: Continuous hot mix supply; wait for haul trucks if needed.
• Monitor Temperature and Uniformity: Thermal differentials indicate defective operations; cessation temperature ~175°F (79°C) beyond which compaction is ineffective (aligned with IRC practices).15

Conclusion

Preventing paver-induced defects requires meticulous planning, calibrated equipment, and adherence to IRC standards like IRC:111-2009 for mix design and IRC:37-2018 for overall pavement integrity. By targeting 98% compaction density, maintaining 150–170°C lay temperatures, and using speeds per the table above, contractors can achieve durable, defect-free asphalt pavements. Regular field testing and training are essential to translate these guidelines into practice.

References

1. Indian Roads Congress (IRC). (2009). Specifications for Dense Graded Bituminous Mixes (IRC:111-2009). New Delhi: IRC.3032
2. Indian Roads Congress (IRC). (2019). Specifications for Dense Bituminous Concrete for Airfield Pavements (IRC:105-2019). New Delhi: IRC.740
3. Indian Roads Congress (IRC). (2018). Guidelines for the Design of Flexible Pavements (IRC:37-2018). New Delhi: IRC.1942
4. Asphalt Institute. (2023). Asphalt Pavement Construction FAQs. Retrieved from Asphalt Institute website.10
5. Pavement Interactive. (n.d.). Compaction Guidelines. Retrieved from Pavement Interactive.15