A composition capable of setting to produce a building material is disclosed. The composition can include from 1% to 30% by weight of an activator, from 1% to 55% by weight of a pozzolan, such as fly ash; from 40% to 90% by weight of an aggregate; and liquid landfill leachate in a sufficient amount such that the composition sets to a building material having a compressive strength of at least 2 MPa, wherein all weight percentages are percent by weight of the total composition. The liquid landfill leachate replaces all or part of the tap water in a conventional composition for forming a building material. The liquid landfill leachate can be recovered after a liquid (typically water) percolates through a landfill and contacts at least one landfilled coal combustion product selected from fly ash, bottom ash, boiler slag, and flue gas desulfurization material. The building material can be a concrete, or a masonry unit.