Applying hollow asphalt concrete technology to drain water, improving road safety

Fast drainage, anti-slip, increased safety

The Institute of Transport Science and Technology is summarizing and evaluating the technology of porous drainage asphalt concrete applied in Vietnam.

According to current standards, for expressways and high-speed roads, a roughening layer is required to ensure safety and smoothness during operation. The technology of hollow asphalt concrete with drainage has been applied for a long time in the world to meet this requirement. However, to apply it in Vietnam, careful research is needed to ensure suitability.

Therefore, the Institute has been researching and testing in the laboratory since 2012; then coordinating with Japanese partners to conduct field testing. In 2016, submitted to the Ministry of Transport to issue Regulations on design, construction and acceptance of hollow asphalt concrete pavement using additives; In 2018, large-scale construction with a length of nearly 30km on the Phap Van - Cau Gie route; In 2020, the Institute developed the standard TCVN 13048:2020 "Hollow asphalt concrete pavement - Construction and acceptance"; In 2022, continue to monitor some sections using hollow asphalt concrete on Thung Khe Pass - Hoa Binh and National Highway 6 - Son La.

The representative of the Institute of Transport Science and Technology emphasized that after 10 years of research and application, it is necessary to summarize and evaluate the application of this technology in Vietnam to make adjustments and recommendations to perfect this technology.

Through monitoring and evaluation of the site, it is shown that porous drainage asphalt concrete has many advantages. In terms of road surface structure, it has high durability, anti-wheel ruts, anti-cracking. In particular, it contributes to ensuring traffic safety for vehicles on the road, because of its fast drainage properties, it increases anti-skid ability, reduces wheel slip, prevents smoke and water splashes, thereby increasing visibility for drivers, reducing the risk of accidents.

Widely applicable standards

According to the Institute of Transport Science and Technology, the results after one month, 12 months and 24 months of construction of the pilot road showed no change in the quality of the road surface during the monitoring period; the road surface was flat, evenly rough, without rutting, peeling, material pile-up, or stone rust. After 105 months, the road surface was flat, with no cracks.

According to Phuong Thanh Construction Investment Joint Stock Company, the entire length of the Phap Van - Cau Gie expressway is 29.3km, and the entire road surface has been covered with porous asphalt concrete for drainage. After 53 months of construction, the results were: Road surface roughness and road surface skid resistance tend to decrease over time but still meet the requirements; wheel ruts appear locally at some locations; permeability decreases over time but is still higher than the required value.

"The application of drainage hollow asphalt concrete technology in recent times has shown good exploitation quality, ensuring safe vehicle speed greater than 120km/h according to Vietnamese standards. The Ministry of Transport has also issued TCVN 13048:2020 "Drained hollow asphalt concrete pavement - Construction and acceptance". This is enough standard to be widely applied in new construction projects as well as road maintenance, improving safe exploitation", said a representative of the Institute of Transport Science and Technology.