High-performance prestressed-concrete ­production in Mexico

Grupo Perse’s product range is broadly based: from industrial structures, to shopping malls, and to residential buildings. The Mexican construction group satisfies all demands by the emerging market. To meet this demand even more effectively, group management decided to build a new plant for prestressed hollowcore concrete floor slab and wall panel production.

At the end of 2012, Grupo Perse therefore contacted the company Weiler GmbH, headquartered in the German city of Gau-Algesheim, around 60 km west of Frankfurt am Main. The German prestressed concrete experts provided the potential Mexican customer with technical details as well as an investment cost analysis for a new plant. Initially, however, the Mexicans decided on one of Weiler’s competitors, owing to a lower quotation.

Impressive high production capacity

Then, at the beginning of 2013, shortly after commissioning the new plant, those responsible at Grupo Perse realized that the new plant would be able neither to deliver the required quantity nor to produce within a reasonable time. The production of one bed took 4 h, subsequent hardening of the concrete even up to 40 h. The hollowcore concrete elements, moreover, required a high percentage of reinforcement, which markedly increased production costs.

Eventually, the company’s management decided to erect an additional plant and once again contacted ­Weiler GmbH. Weiler impressed the management with its quick reaction to the inquiry. The quotation for a new, complete hollowcore production plant was immediately submitted. The contract was signed when a Weiler representative visited Mexico in the following week.

Of particular interest to the customer was high production volume. In addition to the machine facilities for production, the contract included a fully-automated concrete mixing plant with attached skip conveyor and concrete spreader. Furthermore, the facilities included a crane system and the fully automatically controlled heating plant with rapid hardening for the products.

Convincing concept

The engineers at Weiler worked out a convincing concept. Special challenge: the first plant was to be integrated into the overall concept. The new Weiler production line was to be erected directly adjacent to the existing plant. For that reason, the skip conveyor for automatic concrete distribution had to cover a longer distance than is customarily sufficient. A curve was also required.

The Weiler plant itself was impressive with its very high production rates and its shorter hardening times: production per prestressing bed takes only 1 h. And the prestressing wires are released 6 to 7 h later. More than 1,100 m^² prestressed hollowcore concrete elements can be manufactured daily on the four beds, each with a length of 120 m.

The Weiler Max-truder with dual vibration features not only manufactures products of very high concrete strength: it likewise offers the Mexican customers a larger product range. Hollowcore floor slabs and wall panels of between 8 and 45 cm thicknesses can be manufactured on one machine and with various cassettes. At this point, Grupo Perse chose three cassettes for elements of 20, 25, and 30 cm thicknesses. The exchange of one cassette takes only 15 to 20 minutes. The loadbearing capacity of the hollowcore elements manufactured on Weiler machines is around 750 kg/m² – previously it was considerably less.

Remarkable cost savings

Low production costs are an important argument for a profit-oriented and up-and-coming company such as Grupo Perse – in particular if quality does not suffer. With the new Weiler plant, the Mexican company now manufactures around 28 % more economically than on the plant supplied by the first plant delivered by the competitor. These low costs are, among other factors, possible because the Max-truder system processes a considerably drier concrete with less cement than the extruder previously used.

Weiler GmbH consistently follows its concepts of a “clean” and a “dirty” side. That means that dirt-generating tasks – such as the handling of incoming raw materials, concrete preparation, cleaning and maintaining the machine – have been shifted to one side of the production hall. On the other side, “clean” areas have been created for storage yards and loading of the finished products.

Made in Germany

After the concept and its final supplements were presented to the customer, the construction drawings for the production hall were submitted. Grupo Perse immediately started with the earthworks and the construction of the new hall. Four months later, Weiler delivered the first equipment for setting up the beds and the concrete mixing plant. In the spring of 2014, the last production machines left the Weiler plant in Gau-Algesheim. After two months on the high seas, they arrived at the customer’s site in June of 2014. Unforeseeable difficulties at the site delayed the implementation process by a number of months, with the result that the plant was not completed until shortly before Christmas 2014. Production began in early 2015.

After only a few weeks in operation, the Mexican customers were highly satisfied and enthusiastic about the high efficiency of the Weiler plant and the quality of the products manufactured by it. The specialists at Weiler GmbH regard this contract as an unqualified success and important milestone in their work in Latin America. The German machine builder believes that further cooperation with the Grupo Perse is possible. Now that the project is completed, the company “has put a foot in the door to Latin America,” has done a good deal for promoting the quality statement “Made in Germany,” and last but not least, has advanced its status on the international market.