Concrete rehabilitation of the NWK Silo 3 complex in Lichtenburg, South Africa, was completed in October 2023. The Penetron System, a suite of crystalline waterproofing products, was specified to ensure the new concrete silo base structures, as well as NWK’s existing silos, would be impermeable to moisture and water – providing crucial protection from water intrusion and related concrete deterioration – and ensuring the stored crops are kept dry.
A town of around 27,000 in South Africa’s Northwest Province, Lichtenburg is situated in the heart of the region’s “maize triangle,” well-known as a center of farming and ranching. NWK has been a leading agricultural business within the Northwest Province and across the country for over a century. Today, the company offers a wide range of products and services for the agricultural market, including the marketing, handling, and storage of grains and dry beans from the province’s farms – currently boasting a grain storage capacity of 1.7 million tons.
NWK’s new Silo 3 complex in Lichtenburg consists of 8 silo bases, which are the foundation structures of silos used to store various types of grain or silage. The impermeability of these concrete structures is vital to prevent moisture from penetrating into the silo and damaging the stored agricultural crops within.
While silos are familiar, simple structures, they require careful construction, operation, and maintenance. Meticulous control of the temperature and moisture within a silo is necessary to prevent contamination of the stored grain. This is not as simple as it sounds. For example, when the air temperature around the outer walls of a silo falls, the warm air inside the structure can rise, creating convection air circulation. If temperatures inside a silo rise above 90°F (32°C), the quality of the stored grain can quickly deteriorate.
As noted above, if water or moisture seep through an untreated concrete silo base and the moisture level rises above the critical 12% level, the risk of insect infestation, as well as mold and the sprouting of grains, increases, severely affecting grain mass and quality.
“When it came to protecting the harvest stored in its silos, NWK wanted to ensure the new Silo 3 complex – and all of its older silos – would keep the grain dry,” noted Jonathan Whitehead, Technical Engineering Support for Penetron Africa. "However, because of the age of some existing silos, numerous signs of concrete deterioration were evident.”
Upon closer inspection of the existing silo bases, the Penetron technical specialist identified various concrete issues, including spalling, cracks, water leaks, and delaminated expansion joints.
“To prevent further deterioration of the older silo base structures, it was important that a comprehensive repair and waterproofing of the damaged concrete be implemented with the Penetron System,” adds Jonathan Whitehead.
The Penetron System was specified for the repair of the compromised concrete structures of the NWK Silo 3 complex to ensure a permanent barrier against moisture and water ingress. A combination of PENETRON, a topically applied crystalline slurry, and PENECRETE MORTAR, a crystalline waterproofing repair grout, were used to fill in all cracks wider than 0.5 mm and repair other damaged concrete surfaces; in total, 2,000 m2 (22,000 ft2) of concrete were treated. The crack repairs were completed by Delmos, a Penetron-approved applicator, guaranteeing the durability of both the new and repaired silos.
Jansen Van Vuuren, Project Manager at NWK, was pleased with the results: “We quickly realized the Penetron System was the right solution; it provided optimal abrasion resistance, permanent waterproofing from the negative side, and comprehensive concrete rehabilitation. Last but not least, the Penetron solution was also more economical than the other options proposed!”
Concrete impermeability is vital: The NWK Silo 3 complex stores grains or silage. They are now protected from moisture penetration – and the resulting damage to the stored grain – thanks to Penetron.
