Protecting concrete usually means shielding it from the elements of nature or from harsh manmade chemicals. But it’s not just concrete that needs such protection. Corrugated metal pipe, steel surfaces, material hoppers, rail cars and masonry all can come in contact with corrosive or abrasive materials or harsh conditions.
The geotechnical needs of DOTs and other agencies responsible for roads and bridges are vast. Issues include: Culvert repair Soil stabilization Void filling Concrete slab lifting Sinkhole remediation Slope control Slough control in tunneling
Contractor: T. Luckey & Sons, Inc., Harrison, OH
Client: Caterpillar, Lafayette, IN
SCENARIO: In order to easily move some of the largest diesel engines in the world Caterpillar uses an air-powered hydrofoil to lift the massive engines on a cushion of air. For this system to function safely, 3/8” solid steel plates had to be attached to the existing concrete floor. The steel plates were anchored to the floor with 1” bolts and shimmed to create a ¾” (on average) gap between the bottom of the steel plates. The plates were welded together and the welds ground down to form a smooth, flat surface.
A cement-based grout was pumped under the steel plates to fill the gaps. Over time, the cement grout began to break down and fracture severely in multiple locations. This ultimately made the steel plates deflect, causing the hydrofoil to lose its lifting ability and causing an unsafe condition
Caterpillar officials intended to remove the steel plates and underlying damaged cement grout base then re-install the plates and re-grout with cement grout. The cost and downtime required to perform this, however, was simply not a scenario Caterpillar could consider.
SOLUTION: Caterpillar asked T. Luckey Sons Inc. for alternative options. T.L.S. recommended injecting Prime Resins’ Prime Rez 1000 & 1200 through small 3/8” holes drilled through the steel plates on an approximate 3’ on center grid pattern. Caterpillar contracted T. Luckey Sons Inc. to test grout an area approximately 20’x20’.
The test area was a success and after a three-month observation period, Caterpillar contracted T.L.S. for the remaining areas. In some places, multiple passes were needed because some of the underlying cement grout was so crumbled, almost like crushed potato chips.
OUTCOME: The work was completed in five or six days during normal weekend downtime. The floor was traffic-ready after 12 hours of curing. The project was completed with a fraction of the cost of replacement. The hard cost of the injection solution–not even taking into account lost production for a prolonged shutdown–was less than 5% of replacement.
Proven track record: “We’ve built a track record of injecting under toppings,” says Randall Brooks, TLS general manager. “We can show a lot of examples of successful injection so engineers can see that there are viable, cheaper options than tear out and replacement.”