Wikipedia entity: Concrete
Topics: energy; construction; material
Original sentence: Fly ash: A by-product of coal-fired electric generating plants, it is used to partially replace Portland cement (by up to 60% by mass).
Quantified sentence: Fly ash: A by-product of coal-fired electric generating plants, it is used to partially replace Portland cement mostly by mass.
Quantifier: mostly
Percentage: 60%
Specificity: unable