We encourage the use of materials and product with recycled content [and] are committed to selling products that take the environment into consideration.
We encourage the use of materials and product with recycled content [and] are committed to selling products that take the environment into consideration. Û The Home Depot Inc. Environmental Principles
A pilot program with plastic bag-packaged dry mix concrete means less dust to settle these days in the building materials aisles of 24 Virginia The Home Depot stores. Since an April 2005 kick off, it has allowed the home improvement retailing giant to a) reduce floor sweeping frequency; b) lower product spoilage from the replacement of paper with sealed plastic; and, c) observe positive customer response to dry mix concrete with top and bottom handle package design and price points comparable to conventional product.
The pilot evolved from the corporate concrete product procurement staff at Atlanta-based Home Depot and a coal combustion product management specialist, Charah Inc. We were looking for markets beyond concrete block for our lightweight, processed aggregate, and saw how it performed in packaged dry mix, says Charles Price, president and CEO of Louisville, Ky.-based Charah. Our lightweight aggregate has significant yield characteristics. In a standard dry mix, this could mean reduced bag weight on a store shelf, but net hardened concrete on par with conventional aggregate product.
Testing showed that the Charah’s lightweight aggregate, derived from a utility’s slag-like bottom ash and appropriately named PriceLite, could be used in a 29-lb. package at over 55 percent of total mix to provide the equivalent of 40 lbs. of regular dry mix. It produced the branded Project Mix, plus companion products Fast Setting Concrete Mix and Crack Resistant 5000 Concrete Mix Û both sold in 44-lb. bags with equivalent yield of 60 lbs. of conventional dry mix. The three mixes are among 14 plastic bag-packaged products for The Home Depot program, which prompted Charah to become a franchise for Seattle-based Pak-Mix Inc.
All product is bagged at a new plant in Emporia, Va., located near the main East Coast artery, Interstate 95. The aggregate contains processed bottom ash from two Duke Power plants in North Carolina. Charah’s contract with the utility ensures long-term availability of raw material for consistent PriceLite production.
Among benefits The Home Depot can realize from Charah’s packaging and lightweight formulations are products that are easier to carry and less likely to break, coupled with the product differentiation and dust reduction provided by bags made of plastic rather than traditional paper. Those qualities plus the recycled-material content were enough to get the attention of Home Deport Corporate Merchant for Concrete Products Jack Rheinhold. The new packaging is the most exciting, powerful innovation in the bagged concrete industry in 70 years, he contends. The sealed plastic bag is sturdy, and the two handles make it very easy for our customer to transport.
What ultimately paved the way for Charah’s Virginia store pilot, however, was development of plastic packaging film that could be used in high-volume production critical to the economics of low-margin dry mix. Paper-packaged dry concrete mix generally uses valve-fill equipment, but we needed machinery capable of a form-fill-seal process to make the two-handled plastic bag concept work, explains Charah Vice President of Operations Nathan Boone. All of our products are packaged in plastic film with micro perforations allowing entrapped air to exit sealed bags.
A production scheme was developed with Automated Packaging Machinery, an Atlanta dealer for Italian bagging specialist Concetti; and Balcan, a Montreal-based converter who customized plastic film rolls from which packaged concrete mix bags could be drawn. The rolls provide perforations along both sides of the bag, while 4.5-in. top and bottom seals accommodate two holes each, which function as (patent-pending) handles for consumers and contractors. Although film roll changeover is the most time-consuming aspect of switching the bagging line from one dry mix to another, staff seasoning has reduced the process to about 15 minutes.
Charah achieves fill rates of 10 to 13 bags/minute on most concrete mixes and four to five bags/minute on cement-rich mortar mixes. (By comparison, cement companies look for a fill rate of perhaps 20 bags/minute for paper-packaged powder.) The plastic bags’ perforations help limit the de-aerating cycle Û performed by inserting a vacuum probe into a filling bag Û required for higher cement content (> 50 percent) products.
The integrity of the packaging film is critical to production speed and customer satisfaction, says Tom Clinedinst, a 20-year veteran of Perdue Foods who joined Charah as plant manager shortly after the packaging design and equipment were in place. Although he is dealing with concrete versus chicken, Clinedinst sees similarities between his current and former employer. We have 14 different products and need to forecast output to deal with seasonal fluctuation for a large retail account, he says. The packaging innovation upon which Charah is staking a claim in dry mix concrete, he adds, parallels the philosophy of Will Perdue, a forerunner in automated poultry packaging.
The Emporia plant is running two shifts, five days per week. Winter will be devoted to gearing up for demand surges The Home Depot anticipates in late March and early April, according to Charles W. Price, who in his business development capacity has circulated around Virginia, working with store managers and building materials staff to assist in Project Mix and Pak-Mix merchandising, sales and quality control.
Charah officials noted at the beginning of the pilot that the Emporia plant was the first of several bagging operations planned. A follow up to that announcement is likely in the first quarter of 2006.