Stabilizing Cambodia’s Roads

Nov. 1, 2000

From the plains to the densely covered forest to the Mekong River, Cambodia is a popular destination for tourists. In fact, the country subsists first and foremost on tourism. More than 215,000 people travel annually to Cambodia, adding revenue to the economy. Tourists frequent the capital, Phnom Penh, along with Siem Reap, home of Ankhor Wat, a 10,000-ac. complex of dozens of massive Buddhist temples built in the 12th century. Yet about 90% of streets in both cities are unpaved, making travel difficult and discouraging tourists from frequenting other destinations. The limited road network is deteriorating badly as a result of erosion of the laterite soils (sandy clay) that dominate the region. This state of affairs has led visitors to travel on the Mekong River to avoid treacherous roads.

The Ministry of Cambodia has set a plan to rebuild roads to protect the country’s tourism. Cambodia has received $538 million in donor funds for development purposes from international agencies. Some of this money is designated for Phnom Penh, a tourist destination requiring an aesthetically appealing façade. Prime Minister Hun Sen’s focus is on erosion control, which is paramount to the proper construction of Cambodia’s road network needed to revitalize the economy.

Cambodia has seen its neighbor, Vietnam, perform a $60-million renovation of canals using traditional methods of cement and brick, which are time-consuming and costly. But Vietnam has also used a less expensive soil-stabilizing technology that the Ministry of Cambodia believes will start the process of rebuilding the country’s roads quickly and cost-efficiently: Perma-Zyme 11X. The enzyme-based formula, distributed by Charbon International of Tustin, CA, is shipped in a highly concentrated state, then diluted with water and dispersed, causing the soil to bond under compaction into a dense, permanent base that resists water penetration and wear.

A test project was carried out to see how the project would work on one of the country’s much-traveled roads. Darryl Eang, president of the Cambodian Construction Company (CCC), who undertakes commercial construction projects nationwide; Bret Braden, head chemical engineer at Charbon International; and Duane Ebnet, the Hanoi-based VP Asia manager of the Columbus Group (representatives of Charbon International) met to test the product on Rue 360, a road chosen for its high volume of travel by key officials going to and from the Aspara TV station. The project required a low-cost material that could be easily applied. Other possible alternatives were SL-44, Con-Aid, and traditional asphalt and cement, yet Eang saw problems with these applications. SL-44, made from sulfuric acid, threatens the environment; Con-Aid does not hold up well; and asphalt and cement are difficult and costly to transport into Cambodia.

Notes Eang, “Cost was the major factor, and ease of application was important since much of the work would be done by the local villagers themselves.” Workers could make use of water and materials located on-site, and Cambodia’s crops would not be harmed by the nontoxic, EPA-endorsed substance if runoff from the road reached agricultural areas. Application was simple: the soil was bladed, watered with the Perma-Zyme solution, then compacted to 100% of maximum dry density. Ebnet calls it “a high-tech product with a low-tech application.”

The 1.7-km (1.1-mi.) section of Rue 360 was stabilized using less than 80 lit. (21 gal.) of Perma-Zyme along with a topcoat of chip seal on some stretches. The project took 16 days because of heavy traffic and construction staff training. However, CCC’s staff learned the application process during this project. The road was able to receive light traffic the same day it was completed.

Eang feels that road stabilization “improves the quality of life and overall environmental comfort” of Cambodia. He adds, “Just for Phnom Penh, the improvement will reflect a more modern city and thus be more attractive to visitors.” He also points out that soil stabilization, rather than paving, is the ideal option for Cambodia, as completed roads appear rustic, particularly the notable roads around Ankhor Wat that recall an ancient heritage.

Chea Sophara, governor from the Municipality of Phnom Penh, was on-site for the Rue 360 project and is strongly supportive of soil-stabilized roads. He is looking forward to seeing how Rue 360 will hold up throughout this year’s monsoon season. From his experience with the product, Braden says, “Maintenance will be reduced to once every 10 years minimum. Perma-Zyme has successfully stabilized over 15,000 miles of road and endured monsoons, floods, and even Alaskan Perma frost.” Says Eang, “The Ministry of Public Works is eager to designate new areas for renovation.” In fact, should Rue 360 hold up well throughout monsoon season, Sophara is prepared to designate Perma-Zyme as the product of choice for a $3-million renovation plan of 27 Phnom Penh roads to take place at the end of this year.

Braden believes that this project “has made the Cambodians believers that it’s possible to stabilize many roads cheaply.” Potential future projects include repairing riverbank damage to the Mekong River as well as roads in Siem Reap near Ankhor Wat. Using Perma-Zyme to stabilize roads and ease travel, believes Braden, “is just the first step in preserving a world heritage of an unforgotten land and a spiritual Mecca.”

About the Author

Tarla Makaeff

Guest author Tarla Makaeff is a writer based in Irvine, CA.