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LEx: Special Additives

High-Durability Asphalt Concrete Pavements

Introduction

Pavements at container yards, factories, parking lots, and bus stops are frequently subjected to extremely heavy wheel loads and continuous stop-and-go actions.

Traditional solutions, such as cement concrete or semi-flexible pavement, provide good rutting resistance; however, they require long cement curing times or complex cement grouting processes, creating significant challenges for early traffic opening.

To address this challenge, Taiyu researched and developed a special additive named “LEx”, which enables the production of high-durability asphalt concrete pavement. This solution achieves rutting resistance equivalent to semi-flexible pavement while allowing rapid, same-day traffic opening.

Superior Technical Characteristics of LEx Additive

• Easy mixing method: LEx is a plant-mix type additive added directly into the mixer together with Modified Asphalt Type II during asphalt concrete mixture production.

• Smart thermoplastic mechanism: LEx additive possesses thermoplastic properties, automatically hardening as the temperature drops. As a result, the pavement develops its strength immediately upon reaching the traffic-opening temperature, eliminating the need for long curing periods like cement.

• Excellent rut resistance:

  • Wheel Tracking Test results show that the Dynamic Stability (DS) of LEx asphalt concrete reaches 21,000 to 63,000 passes/mm, significantly outperforming conventional modified asphalts such as SBS, TPS, or TPP (which only reach 3,000–9,000 passes/mm).

  • The deformation after 60 minutes (D60) of LEx asphalt concrete is even lower than that of semi-flexible concrete, demonstrating equivalent or superior rutting resistance.

• High oil resistance: In a 48-hour kerosene immersion test, the LEx asphalt concrete layer showed virtually no dissolution, maintaining the specimen’s shape without aggregate stripping typical of standard asphalt concrete.

• Low temperature sensitivity: The elastic modulus of LEx asphalt concrete shows minimal variation across ambient temperatures (0°C to 40°C), maintaining high stability and load-bearing capacity even during hot summer conditions.

Practical Application Results in Japan

• Project: Rehabilitation of a main road with 3 bus stops in Japan, covering a total construction area of 5,200 m².

• Construction solution:

  • The main roadway layer used dense-graded asphalt concrete, while the bus stop areas utilized LEx asphalt concrete.

  • LEx was paved using conventional asphalt paving equipment, allowing a direct mixture changeover right in the paver hopper.

  • This process completely eliminated construction joints—which are typically weak points prone to distress.

• Effectiveness in shortening traffic opening time:

  • Compared to the initial design using semi-flexible pavement (requiring a total of 8 days), switching to LEx asphalt concrete eliminated demolition work at the bus stop areas and the cement grouting process.

  • Actual construction time was reduced to 6.5 days (shortened by 1.5 days, equivalent to approximately a 20% reduction in construction time).

• Long-term durability:

  • After 4.8 years of operation, the pavement surface at the bus stop area remains in excellent condition, showing no signs of rutting or cracking.

Conclusion

The LEx additive researched and developed by Taiyu offers an optimal technological solution for heavy-load and high-traffic-density areas. It guarantees exceptional rutting resistance while significantly shortening construction schedules and reducing long-term operational costs.

Bibliographic Citation & Publication Details

Below is the complete citation of the research paper for publication attribution:

• Paper Title: Development of Special Additives for Highly Durable Asphalt Pavement.

• Authors:

  • Takashi Okumura (Technical Research Laboratory, TAIYU Kensetsu Co., Ltd., Nagoya, Japan).

  • Nguyen Quang Phuc (University of Transport and Communications, Hanoi, Vietnam).

  • Vi Van Hanh (General Director of TAIYU Vietnam Co., Ltd., Hanoi, Vietnam).

  • Asako Nakamura (Global Business Department, TAIYU Kensetsu Co., Ltd., Nagoya, Japan).

  • Hiroshi Nagasaki (Technical Research Laboratory, TAIYU Kensetsu Co., Ltd., Nagoya, Japan).

  • Tomoki Murakami (Technical Research Laboratory, TAIYU Kensetsu Co., Ltd., Nagoya, Japan).

• Publication / Journal: Lecture Notes in Civil Engineering (LNCE), Volume 733, Pages 52–60.

• Conference: The 5th International Conference on Sustainability in Civil Engineering (ICSCE 2024), October 23–25, 2024, Hanoi, Vietnam.

• Editors: Nguyen-Viet Thanh, Long Nguyen-Ngoc, Thanh Bui-Tien, Tuan Nguyen-Quang, Guido De Roeck.

• Publisher: Springer Nature Singapore Pte Ltd. (Published in 2026).

• DOI: https://doi.org/10.1007/978-981-95-1072-6_4

• Download link here

• ISSN / ISBN: ISSN 2366-2557 / ISBN 978-981-95-1071-9 (eBook: ISBN 978-981-95-1072-6).