Although bitumen typically makes up only 4 to 5 percent (by weight) of the pavement mixture, as the pavement's binder, it is also the most expensive part of the cost of the road-paving material.
ɔːlðˈoʊ bɪtˈuːmɛn tˈɪpɪkli mˌeɪks ˌʌp ˈoʊnli fˈoːɹ tə fˈaɪv pɚsˈɛnt baɪ wˈeɪt ʌvðə pˈeɪvmənt mˈɪkstʃɚ, æz ðə pˈeɪvmənts bˈaɪndɚ, ɪɾ ɪz ˈɔːlsoʊ ðə mˈoʊst ɛkspˈɛnsɪv pˈɑːɹt ʌvðə kˈɔst ʌvðə ɹˈoʊdpˈeɪvɪŋ mətˈɪɹiəl.