Merevolusi Konstruksi Jalan: Munculnya Teknologi Asbuton dalam Rekayasa Perkerasan Jalan

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beritapekanbaru.com -The bridge in Jiangsu, China, is truly a sight to behold. Stretching elegantly across the vast waters, it appears to divide the sea while seamlessly connecting two islands. The smooth asphalt surface of the bridge ensures that vehicles can glide effortlessly, allowing for a swift and comfortable journey to their destination.

What many may not realize is that the asphalt paving this magnificent bridge is not derived from petroleum-based sources. Instead, it is composed of Buton Asphalt, commonly known as Asbuton, which originates from Buton Island in Indonesia. This remarkable natural resource is also utilized in the construction of highways across China, including those in Shanghai and Anhui provinces.

Despite its international recognition, Asbuton remains underutilized in its homeland, Indonesia. It has often been overlooked in favor of imported petroleum-based asphalt, which is more commonly used by the government and construction contractors. However, Asbuton is a natural gift bestowed upon Indonesia, one of the few countries in the world endowed with vast deposits of natural asphalt. With its abundant reserves and superior properties compared to conventional asphalt, Asbuton holds immense potential for infrastructure development.

Asbuton presents a viable alternative to petroleum-based asphalt, offering a sustainable solution for road construction. With an estimated deposit of 663 million tons, containing an average asphalt content of 20%, this resource equates to approximately 132 million tons of pure asphalt. Considering Indonesia’s annual asphalt demand of 1.2 million tons, and the fact that domestic production (from Pertamina) meets only about 600,000 tons (50%), the country has heavily relied on imports from suppliers like Esso, Shell, and Middle Eastern producers. By substituting imported asphalt with Asbuton at a rate of 600,000 tons per year, Indonesia could achieve asphalt self-sufficiency for over 220 years.

However, leveraging Asbuton for large-scale applications presents several challenges. Extensive research, development, and technical refinements are required to optimize its usage. The responsibility falls on the Indonesian people to champion the utilization of this valuable resource. While foreign interests may eventually see the business potential, their primary motivation will be profit, not the welfare of the people of Buton.

The Indonesian government, particularly the Ministry of Public Works and Housing, has consistently advocated for the broader adoption of Asbuton. Unlike petroleum-based asphalt, which has long been familiar to road construction professionals, Asbuton requires specialized knowledge and handling techniques. Although research has demonstrated its effectiveness as a binder for road pavements, widespread application remains a challenge due to manufacturing complexities, planning difficulties, and implementation issues that must align with established specifications and guidelines.

Many stakeholders perceive the use of Asbuton as more complicated than petroleum-based asphalt. Traditional asphalt consists of 99% bitumen with consistent characteristics, making it easier to apply, whereas Asbuton contains 18–35% bitumen and a high mineral content (65–82%). Furthermore, its storage properties present additional hurdles—certain types of Asbuton tend to clump, particularly those with high penetration values. This complicates processing in asphalt mixing plants, requiring manufacturers to ensure the material remains in granular form upon usage, which adds to production challenges.

Moreover, understanding and implementing Asbuton-based road construction guidelines is not straightforward. As specifications evolve through feedback from field practitioners, continuous improvements are necessary. Effective communication among researchers, producers, contractors, and government agencies is essential for refining and standardizing Asbuton application methods. Training programs, technical support, workshops, and collaborative initiatives must be promoted to bridge the knowledge gap and enhance practical implementation.

Since the 1980s, Asbuton has remained a subject of national discourse, experiencing fluctuations between optimism and skepticism. Without strong commitment and perseverance—what Minister of Public Works and Housing, Basuki Hadimuljono, describes as "high militancy"—Asbuton might have been abandoned altogether. Pioneers in the field, including government bodies, private companies, and researchers, have continuously strived to develop viable Asbuton-based technologies despite facing numerous obstacles.

The evolution of Asbuton utilization can be categorized into two key periods: the pre-2000 era, marked by the development of Lasbutag (Lapisan Asbuton Beragregat), and the post-2000 era, characterized by the diversification of Asbuton-based technologies. In the Lasbutag era, applications were limited primarily to light-traffic roads, with notable methods including Latasbusir, Superlasbutag, Asbumix, Teknobutas, and Bitumen Mastik Asbuton. However, these technologies, reliant on cutback asphalt and kerosene-based mixtures, failed to gain widespread acceptance due to economic and quality limitations.

Despite setbacks in the Lasbutag era, the lessons learned paved the way for advancements in the post-2000 era. This period saw the integration of Asbuton into various road construction techniques, mirroring petroleum-based asphalt applications. The focus expanded beyond light-traffic roads to encompass all road classes, including heavy-traffic highways.

Raw Asbuton, containing approximately 5% light oil, has a penetration value of 180 dmm. When refined into granular Asbuton Type B 50/30 by reducing light oil content to 2%, the bitumen concentration increases to about 27%, with a penetration value of 50 dmm—closely matching conventional asphalt grades. This refinement allows Asbuton to be used without additional softening agents, making it a more feasible alternative.

Today, Asbuton-based road construction technologies are proving competitive against petroleum-based asphalt. Increasing adoption in national and regional road projects highlights its growing credibility. Reports indicate that since 2016, the Buton, North Buton, South Buton, and Wakatobi regencies have fully implemented Asbuton for their road infrastructures. This movement gained further momentum with Southeast Sulawesi Governor’s Decree No. 412 of 2020, mandating Asbuton usage for provincial and municipal road construction and maintenance.

The rise in the number of Asbuton-producing companies further underscores its economic viability. Currently, 23 companies under the Indonesian Buton Asphalt Development Association (ASPABI) collectively produce approximately 865,100 tons per year—an impressive increase compared to the Lasbutag era, which saw only around five active producers.

Asbuton can serve two primary functions in road construction: as an additive to enhance petroleum-based asphalt quality or as a substitute, either partially or entirely. Some technologies, such as LPMA, Cape Buton Seal, Butur Seal, and Pure Asbuton, can completely replace petroleum-based asphalt, making them ideal for maximizing Asbuton utilization. Others, like CPHMA and Hot Mix Asbuton B 50/30, incorporate up to 75% Asbuton while retaining a fraction of petroleum-based asphalt.

In 2020, Asbuton-based technologies were successfully implemented on heavy-traffic national highways, proving their resilience against deformation and rutting. This breakthrough demonstrates that Asbuton is no longer limited to light and medium-traffic roads but is now a viable alternative for all classes of road construction.

With continued technological innovations and government support, Asbuton is poised to become a cornerstone of Indonesia’s road infrastructure. The journey may still present challenges, but the rewards—a self-sufficient asphalt industry, economic benefits for Buton Island, and a more sustainable future—make the pursuit worthwhile. As Indonesia moves forward, embracing Asbuton is not just a matter of infrastructure development; it is a testament to the nation’s commitment to harnessing its natural resources for long-term prosperity.