After the Middle Ages the Roman Empire, the Middle Ages began. In the meantime, asphalt road asphalt lost its former glory. People use asphalt experience gained over the past millennium is almost lost and exhausted, until the eighteenth century, people began to re-start learning to use the pitch. In the year 1000 the Arabs began to extract bitumen (Bitumen) from natural bitumen (Naturasphalt) in. The method is heating natural asphalt (Naturasphalt) until the bitumen (Bitumen) from precipitation. Natural rock asphalt Kawakita is based molecular weight of up to ten thousand of asphaltenes as a major component of Shandong asphalt, the chemical composition of carbon 81.7% Wholesale asphalt, 7.5% hydrogen, 2.3% oxygen, 1.95% nitrogen, 4.4% sulfur, aluminum 1.1% , 0.18% silicon and 0.87% other metals. Wherein the asphalt content, the content of carbon, hydrogen, oxygen, nitrogen, sulfur, high asphaltene molecules almost every all contain polar functional groups of the above elements, making the rock surfaces produce a strong adhesive force. Bitumen, wholesale, three level chemical quality assurance (certified merchants) are provided by Chemical Co., Ltd. Jinan three levels. Jinan three ping Chemical Co. (www.sanpinghuagong.com) is specialized in "calcium nitrate, magnesium nitrate, zinc nitrate, magnesium sulfate, calcium sulfate, barium sulfate, ferrous sulfate," the enterprise, the company adhering to the "honesty, hard service "concept, to provide you with the highest quality products and services. Welcome to inquire! Contact: Su Jingli.