Evaluation and identification of parameters affecting the penetration of emulsion bitumen on aggregates

ABSTRACT More penetration of the prime coat increases the stabilisation thickness of the sub-asphalt layer and makes it more difficult for water to penetrate. Therefore, the purpose of this study is to identify the effective parameters on the penetration of Cationic Emulsion Bitumen (CEB) and investigate their effects. Short and long-term penetration tests are used. For better evaluation, two types of silica and limestone aggregates are selected in dry and wet conditions. To better compare the results of penetration, the penetration of MC250 cutback bitumen was also measured. The results show that among the identified parameters, the maximum penetration increase is influenced by the time of penetration, the material of aggregates, aggregate humidity, type of prime coat, kerosene percentage, and colloid mill speed which is equal to emulsifier percentage and the percentage of pure bitumen. Also, the least effect is observed for increasing soap temperature. Another result is that the CEB penetration in limestone aggregates is inappropriate in all cases. However, the penetration of CEB in silica aggregates in almost all cases provides minimum requirement so that the moisture being most effective to increase it. The value of MC250 penetration in limestone aggregates is only appropriate for wet and long-term conditions.