Lehigh Cement officials formally commissioned a 20,000-metric-ton, multi-compartment, environmentally friendly silo at the company’s Leeds, Ala., mill late last year with an open house. With a 79-ft. outside diameter, the 239-ft. structure stores the operation’s three product lines: Type I/Type II general purpose cement; Type V specialty cement, used mainly for concrete pipe production; and Type C1157 HE, a limestone-based powder suitable for mix designs in infrastructure projects.
The event saw tours of “D” Silo and a construction overview by Leeds Plant Manager Rick Parker, who affirmed, “A driver can now load the truck in well under 10 minutes.” Among special features he highlighted were environmental controls to produce a virtually dust-free product-loading system and two scale-equipped truck lanes, plus one railcar scale, to allow loading more than 300 tons per hour.
With Hopkins, Minn., slipform specialist T.E. Ibberson Co. at the helm, work on “D” Silo spanned about two and a half years and saw placement of 6,200-plus yards of concrete. The contractor executed a design and construction plan involving Lehigh Cement parent and sister operations: Heidelberg Technology Center formulated mix design to maximize silo service life. The local plant of Birmingham, Ala.-based Sherman Industries supplied a mix containing 60 percent C1157 HE cement—Leeds’ own Type HE, MS [High Early, Moderate Sulfate]—and 40 percent C989 ground granulated blast-furnace slag with a low water-cement ratio.
Rounding out “D” Silo’s Lehigh-backed supply chain was Hanson Building Products, which fabricated the structure’s precast components, equal to about 500 yd. of concrete. The result, Lehigh Leeds management affirms, is a lower carbon footprint, with concrete forming a structure engineered for 100 years.