Hurricane Harvey Relief Fund, Construction Products Concrete Countertop Mix. Imperial Countertop Mix is engineered to be both lightweight and exceptionally strong. It is suitable for both indoor and outdoor use. Its described as an exclusive blend of additives and ultra fine fibers that will transform a 60 lb. Utilize our lightweight concrete to reduce weight by 40% to 60%. Some bags will provide the yield of concrete in cubic feet; others may tell you how many square feet of countertop you can produce at a specified thickness. WHAT IS COUNTERTOP MIX? Our Flowcrete GFRC Admixture. Precast Concrete. of Acrylic Polymer if used). Subscribe now Concrete is very heavy.