Asphalt water molecules

The user should remember, however, that when a barrier material is emulsified or extended with a solvent, the coating made from it does not solidify totally until the water or solvent present in the formulation evaporates, and when this evaporation occurs, the structure that remains behind has tiny pores, holes or cavities where the water or solvent was, and chemicals, especially those with tiny molecules like HCI, can slowly diffuse through it-something they can not do through the dense hot asphalt. Further, if the brickwork covers this type of coating or membrane too soon, some of the water or solvent will be blocked or trapped in it. If water remains so that the emulsion does not harden completely, any water-borne chemicals can cause the asphalt to reemulsify and so wash away, destroying the barrier. If solvent remains, the membrane can rather easily be penetrated. 

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