Aspen Round Concrete Planters have a unique style and sizes for flowers, trees, and shrubs. Beauty and utility. All Vandal-resistant precast concrete products shall have a minimum compression strength of 5,000 psi at 28 days. There shall be a maximum of 4-6% air entrainment and 3/8 inch rebar reinforcement, engineered to withstand severe structural stresses. The exposed aggregate texture is washed, cured, and sealed to enhance the stone colors. The smooth surfaces have color dyes throughout mixture for consistent color and protective sealer that prevents dusting.