挑战

纽约市的道路铺设和维护工作异常艰巨。许多街道状况不佳，混凝土老化，地下基础设施脆弱。2012年，纽约市交通局（NYCDOT）为第一大道的50个街区苦苦寻找解决方案。更换45厘米（18英寸）厚的混凝土路面成本高昂，耗时漫长。薄层覆盖虽然有所帮助，但只能延长几年寿命，之后仍需进一步修复。

Looking for a solution, NYCDOT contacted Axeon Specialty Products. Axeon suggested their High-Performance Thin Overlay (HPTO) mix design with a PG 76-28 modified asphalt binder. In consultation with Kraton, Axeon proposed an alternative using high-performance polymer-based HiMA™. With a start date of September 2012, the NYCDOT paved two blocks, each with the two binders. A year later, no rutting or cracking was observed. Looking for the best long-term solution, NYCDOT opted for the HiMA binder.

Paved in fall 2013, the overall project started with 1.3 cm (.5 in) micro-milling for a smooth surface with extensive crack sealing. A crack attenuating grid was attached with PG 76-28 binder, followed by 3.8 cm (1.5 in) of HPTO/HiMA mix with a warm mix additive. A total of 11,000 tons was placed over 53 city blocks at night, with paving completed in only three weeks. The mix was fixed at about 149°C (300°F), and 95 percent density was ultimately achieved.

By the end of 2019, the pavement is still in excellent condition, and NYCDOT stated that performance exceeded their expectations. By using the HPTO mixture featuring HiMA technology, they were able to leave the deteriorated concrete pavement in place while fully rehabilitating the surface. As a result, NYCDOT saved over 80 percent of what it would cost to remove and replace the old pavement.