The Role of Hydroxypropyl Methylcellulose (HPMC) in Wet-Mix Mortar Wet-mix mortar is a composite material composed of cement, fine aggregates, additives, and water, with its performance determined by the precise proportioning of these components. After batching and mixing at a production plant, the mixture is transported to the construction site via agitator trucks and stored in specialized containers for use within a specified time frame to ensure optimal workability.