Type IS, paired with focused technical service, a good fit for small but healthy industry segment
Don Mullin doesn’t mess around when it comes to concrete. As owner of Concrete Express, a Salem, Conn.-based mobile mix provider, his business is on the line with every load of cement delivered. Unlike ready-mix operations, which have the ability to roll through a “false set” problem or a cement product that characteristically absorbs water at a faster rate, “We in the mobile mix industry are very sensitive to any cement product changes because we only have a nine-foot mixing cycle,” says Mullin. “We’ve got to be right on the first pass. We can’t put more water in and then take it out again—once you’re a pickle, you can’t be a cucumber again,” he jokes.
|Type IS blended cement combines portland and slag cements into a single product form. For concrete producers with limited silo capacity, blended cement allows them to achieve benefits of using slag cement in concrete—like greater strength and durability—without multiple silos. A Type IS blend performs similarly to a Type I portland cement and conforms to ASTM C595, “Standard Specification for Blended Hydraulic Cements.”|
Mobile mix operations are ideally suited for small jobs. The operations combine all the necessary equipment and materials on one truck, mixing the concrete on-site: the concrete ingredients are conveyed into a nine-foot auger, which mixes the material at the location, supplying loads as small as a quarter of a yard. With smaller delivery equipment, they can squeeze into tight job site areas, supplying loads as small as one yard to complete projects like deck piers, equipment pads, sidewalks and other small projects.
So when Rich Sullivan, territory manager for supplier Lehigh Northeast, approached Mullin with the idea of trying a load of the company’s Type IS portland blast furnace slag blended cement in place of conventional portland cement, Mullins replied: “you’ve got to be out of your mind.” With his one-silo business, there would be no margin for error.
Customized service sells
Mullin was more than a little skeptical of using the type IS cement, but Sullivan guaranteed the product and offered to pull it from the silo if it didn’t work. “Don was having false-set problems with a regular portland mix, as were five or six of the other mobile mix guys in the area,” says Sullivan. “I explained that he wouldn’t have the same problem with the blended cement, because the heat of hydration would be slowed down.”
Sullivan walked Mullin through the basics of the product, providing him with the technical information he needed, as well as a commitment to finding a guaranteed solution. Mullin appreciated the services focused on his product. The customized service sold him on the idea, and he took a load to try.
Defining the “fluff factor”
Initially, the process required recalibrating the equipment. Type IS is less dense than conventional portland cement, and in a mobile mix operation, the material must be proportioned by volume—so Sullivan had to determine the unit weight of the loose material. A cubic foot of the material weighed less than the typical 94 lbs. of conventional portland cement, so Sullivan provided the ‘fluff factor.’ The Type IS weighed 78 lbs, amounting to a 17% increase volumetrically—where 27 tons of portland cement would fit easily, he could only fit 23 tons volumetrically of the IS material.
While this had no effect on the equipment’s ability to produce concrete, it did impact the company’s storage needs. In the field, Mullin uses high-tech mobile mixers from Elkin Manufacturing Inc., which have the ability to meter and volumetrically dispense the cement at a consistent rate, ensuring precise product.
The Lehigh Type IS is inter-ground, and Sullivan says that in the summer months, the target range is 33 to 35% slag; in the colder months, the range is reduced slightly to 30 to 33% slag. “The beauty of the inter-ground material is that the slag granules are harder than cement clinker, so by the time the ball mills get the slag to the desired fineness, the cement blaine has gone from a typical Type I portland blaine to a Type III high early blaine,” explains Sullivan. “The high early characteristic of the finer-ground cement provides earlier strength gain to a blend that would otherwise have seemed destined for delayed strengths because of the reduction of portland cement content.”
Non-traditional product serving a traditional market
The result: Mullin has been using Type IS for more than two years, and five more mobile mix companies in the area have converted to Type IS. “It’s a really good product,” says Mullin. “Like peanut butter and jelly, it’s a good merger—individually, they’re both decent products in the right application.” He is quick to say that he thinks mobile mix operators should see for themselves if the product is a good fit for their specific needs. But for him, it works: “The IS product has significantly reduced bleed water and is more manageable, and achieves a higher strength gain. The blend is more predictable than [ordinary] portland cement, and as long as they seasonally adjust it, it’s a superior product,” says Mullin.
Solid customer service really cinched the deal, he adds. Even with an excellent product, “you have to go back to basics with the sales of everything.” In a market where people don’t like change, providing the right level of technical support will help producers improve their product and expand the market. “Work with people, monitor your results, and prove yourself,” he says, and the business will come to stay.