Hot Weather Grouting
A few techniques and the right product can ensure proper installation on critical projects.

-Byron D. Hanson
ASTM, CDT, Lead Technical Back-up,
Professional Field Representative
Civil Engineering Technician
L&M Construction Chemicals, Inc.

The critical grout project was a solvent refinery nestled deep in the heart of the oil patch, gold coast of southwest Louisiana. The contractor was faced with the challenge of grouting in real world conditions: peak day temperatures over 100 degrees Fahrenheit and burdened with a fast track schedule. The originally specified grout was setting up in short time in the wheelbarrow. The elevated temperature conditions were miserable enough, but the additional aggravation of the too fast setting grout was clearly an unwanted and unwelcome burden.

Fortunately, L&M's representative was simultaneously calling on the refinery, promoting L&M's chemical resistant joint filler, Joint Tite. The refinery facility engineering staff escorted the L&M representative to the grouting site and asked if there was a product in L&M's inventory that would work in the elevated temperature environment. After studying the situation, he recommended L&M's Crystex Non-Shrink Grout. Crystex is L&M's top-of-the-line, cement-based, high strength, non-shrink grout. It's extended work time has been the hallmark of Crystex since its introduction in 1976, as it can attain a fluid consistency and remain fluid for over an hour, even in 100 degree Fahrenheit summer conditions. The contractor and the owner gave the go ahead to start grouting with Crystex.

L&M's local representative and a factory trained technical representative were invited to the site to set up the grouting protocol and to conduct safety classes. The items to be grouted included a wide variety of challenges, including crane support base plates, machinery sole plates, and tank car support rails of the rail spur coming into the refinery.

Once the safety issues were covered with the help of the refinery safety director, the L&M crew set about training the contractor's crew to mix and place CRYSTEX grout at the elevated temperatures. The first item of business was to get a system to supply cold water in sufficient volumes for the grouting. All the cold water presently available was being consumed by the crew to ward off the rigors of working outside in the one hundred plus degree heat. The L&M crew showed its characteristic compassion and instructed the contractors crew in how to construct a "Cajun cooler" to produce ice water. The assembly was simple. Filling a 55-gallon drum with alternating layers of rock salt and ice a water hose is then laced between each layer of ice and salt. In a matter of minutes the delivery end of the hose will produce a continuous supply of ice-cold water, for as long as needed. Simply make sure that the ice and salt layers in the barrel are replenished. The contractors were also counseled to never shut the flow of the water off, as any non-moving water in the hose will eventually freeze solid.

The contractor's crew worked with a large, gasoline-driven mortar mixer with a back-up machine available for emergency use. The ample supply of cold water allowed the crew to water cool the sun-heated mixer prior to each use as well as to properly presoak the sun-baked metal bases and concrete foundations prior to being grouted. This cooling and presoaking was excellent preparation for placement of the fluid, self-leveling consistency Crystex grout. Overnight soaking of the concrete foundation is recommended for most grouting projects.

Critical void to be filled under rail with fluid Crystex Grout placement during hot summer temperatures.
Carpenters did an excellent job of enclosing the metal bases and rails to be grouted. The wood forms were built to be about one inch higher than the bottom of the base or flange to be grouted. The forms were caulked to be watertight. The forming was treated with L&M's Debond Form Coating and in most cases, removed the following day and reused.

After removing any excess soaking water, the grouting commenced. To the mix batch the contractor's crew added a pre-measured amount of sufficient cold water to five 55-pound (25 kg) bags of L&M Crystex grout. Crystex remained fluid in the wheelbarrow for at least an hour and the crew was instructed to install the grout in a rapid and continuous manner.

Curing of freshly placed grout is recommended, especially under hot weather conditions. Typically wet rags are placed on the exposed grout shoulders of the in-place grout, and then covered with plastic sheeting. Curing rags should be re-wet as needed, and left in place for a minimum of 3 days. On this particular project the contractor came up with a slick idea. Using the empty Crystex bags, which are constructed of durable Kraft paper and a poly inner-liner, the contractor's people soaked the opened Crystex bags in cold water and blanked the grout beds with multiple layers of water-soaked bags. The water-soaked bags were held in place with sand back fill and lumber. (Nice recycling job!)

The end result was that the contractor finished ahead of schedule and the grouting was in place and functioning for the refinery and the rail siding. L&M Crystex can repeat this performance on your project. So the next time hot weather grouting becomes a necessity, remember that elevated temperatures can be overcome with the right grout and the right training. At L&M we can give you both. We encourage your questions; let us know how we can serve you.

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© 2002 L&M Construction Chemicals, Inc. | ConcreteNews Summer 2002.

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