Following initial contact in 2008, the relationship between Spiroll and Vikon has gone from strength to strength. With Spiroll’s vast experience in hollowcore production and Vikon at the forefront of promoting modern precast technologies in Russia, the partnership showed great promise from day one.
The most recent beneficiary of this shared expertise is ZKPD-70, a construction company based in Nizhniy Novgorod, situated between Moscow and Kazan. ZKPD-70 recruited the services of Vikon following the acquisition of a contract to build 5,000 apartments in the city using precast frame technology and hollowcore slabs. Vikon provided ZKPD-70 with the precast design of the buildings; and then detailed a package of production equipment necessary to manufacture the individual elements. This included prestressed beam and reinforced column molds, a stair mold and universal casting beds for wall panels. With installation supervised by Vikon, a complete Spiroll hollowcore production setup was installed.
Heart of hollowcore production
The Universal Extruder is the heart of Spiroll’s hollowcore production system. Its unique design ensures that production is low cost, extremely reliable and the finished hollowcore is of the highest quality. The functional design means it is very easy to use, set up and maintain.
The Extruder is unique as it utilizes an auger drive combined with a 9,000 rpm high-frequency vibration system. It produces hollowcore slabs with good early strength; a consistently high quality finish; low cement content; high load bearing capacities; excellent strand bond and low camber. The Extruder requires one man to run the machine on the production bed and once it has been set up correctly it simply requires the mix to be put in the hopper to begin production.
The same energy that feeds the concrete mix through the machine and forms it into the final precast slab also provides the motivation to drive the extruder along the bed. This natural process propels the extruder along the casting bed and allows the compacted concrete to reach the required density.
Intense high-frequency vibration
The Spiroll system uses an extremely dry concrete mix and lower cement content than other machines (typically a water/cement ratio of approximately 0.3). Due to the intense high-frequency vibration and pressure within the machine, the concrete mix is ‘plasticized’ during the short time that it is passed through the extruder, which allows it to be molded and formed into the required section.
The formed slab then reverts to its ‘dry’ state and reaches such a high density that it is possible to stand on the slab immediately after the extrusion process. After a period of natural or accelerated curing, depending on the requirements of the customer, the slabs are then cut to length, stripped from the casting bed and transported to the storage area.
Precast frame technology
In order to meet the demands of modern construction, fast lead times, reduced costs and improved quality are all required. The method championed by Vikon and increasing in popularity throughout Russia is precast frame technology. This method of construction boasts the following advantages: optimal structural design, simplified frame assembly, up to 30% reduction in construction costs, increased volumes, flexible layout apartment planning, fast erection – up to 5,000m2 with one tower crane.
The principle at the core of precast concrete frame technology is that the load-bearing frame is assembled from the prefabricated elements and structures. A precast concrete frame consists of three main elements: vertical bearing columns, prestressed beams and floor slabs. The connective joint between the precast components is solid, and the precast concrete elements form the frame of a building.
Another factor that should be considered with the use of precast frame technology is that it offers good stability in areas with seismic activity. As precast elements are plant manufactured and under strict quality control, the integrity of the finished buildings can be guaranteed.
Commissioning and on-going support
To help gear up for the official opening of the factory, ZKPD-70 also invested heavily in their offices and factory infrastructure. As part of a support package, Vikon supplied 12 employees from their factory in St. Petersburg to help train the staff at ZKPD-70, and ultimately hand over production of the precast elements within one year.
The machinery was commissioned over a 3-day period by a team from Spiroll with great results and achieving a high-quality product from the outset. On the final day of the commissioning visit, Spiroll’s team were invited to attend a ceremony involving the placing of the first precast column on site. The local mayor and senior employees of Vikon and ZKPD-70 were also in attendance.
The delivery on this project, from the initial precast frame design through to the fixing of individual elements on site, shows the level of service and support than can be expected in future turnkey projects involving Spiroll and Vikon, whether in Russia or CIS countries. This success will be built upon in new proj-ects already underway with SKC Beton in Kazakhstan, Fedorchenko in Ukraine and USK in Russia. The common values of efficiency, quality and shared desire to bring modern precast technology to markets around the world will certainly stand the partnership in good stead for the foreseeable future.