Terry Waschke

Alaska Concrete Technologies Inc. dba Mobile Concrete and Grout of Alaska is a locally owned company incorporated in 2000, providing concrete and grouting services throughout Alaska. Terry Waschke, owner, has over 40 years of experience in the production, pumping, and quality control of concrete and grout. Portable batch plants, mixer trucks, volumetric mixers, and super bags, individually, or in combination, are used for concrete and grout production, anywhere in the state.

We use compaction grouting equipment to produce and inject low-mobility grout, to stabilize poor soils under roads, railroads, buildings, or airports, and raise to desired elevations. Injection pipes are driven down to stable ground and grout injected to densify and lift the ground, so there is minimal ground disturbance, and many times buildings can be raised from the outside.

Cellular concrete with densities down to 30 pcf is used for many applications including backfills, void fills, slab jacking, slip line grouting, and abandonments. It can be pervious or closed cell and has excellent insulating characteristics for cold regions.

Terry has extensive experience working with labs to design concrete and grout mixes utilizing a wide range of admixes for job-specific applications. The strength range extends from 12,000 psi concrete to 75 psi cellular concrete, with set times from 1 hour to 3 days. That knowledge, along with the equipment to produce concrete and grout, combined with many years of pumping, puts Terry in the unique position to know what equipment, materials, and methods would be the most cost effective and efficient for local and remote projects.

Concrete Services

Terry has 30+ years experience batching with computer-controlled dry batch and central mix stationary plants, a computer-controlled portable dry batch plant for remote projects on the road system, a volumetric Mixer with computer for local and remote projects, and a Fastway for remote projects with local aggregates, accessible by road, barge, or ferry.

For many remote projects, pre-weighed super bags of aggregate and pre-weighed super bags of cement are used to batch anywhere a conventional mixer truck can be shipped to. Super bags can be shipped from known suppliers with proven mix designs, through many ports in Alaska as well as Seattle. Consistent high-quality results are achieved by strictly adhering to the mix designs and using a water meter. It also is important to pay close attention to the addition of admixes and use testing equipment to make sure air and slumps are accurate.

Locations around the state Terry has batched include: Anchorage, Whittier, Canyon Cr Bridge, Seward, Hurricane Gulch, Cantwell, Healy, Fairbanks, Circle, Anaktuvuk Pass, Atigun Pass, Jim River, Wainwright, Kotzebue, Bethel, Kwethluk, Nikolai, Platinum, Manokotak, New Stuyahok, Koliganek, Kodiak, Sand Point, Chignik, False Pass, Dutch Harbor, Atka, Adak, Shemya, and Petersburg.

We can supply materials and equipment or use yours.

Projects such as bridge deck overlays and tunnel linings require concrete or shotcrete strengths in excess of 10, 000 psi. Very low water to cement ratios are used to achieve high strengths, in conjunction with additives like Silica Fume, along with plasticizers, retarders, and air entrainment admixes. Stringent QA/QC measures are critical to achieve consistent results no matter where it is produced. Bridge deck overlays have been done in Anchorage, Cantwell, Hurricane Gulch, and Dutch Harbor. Shotcrete with steel fibers was produced on-site for the Whittier tunnel, and during the winters of 2003, 2016, and 2017 we consistently produced concrete and shotcrete with super bags for Lowell Cr Tunnel in Seward in excess of 12,000 psi in the dead of winter.

Cellular Concrete is made with pre-formed foam added to either a sand, cement, and water, or neat cement and water, to achieve densities between 30 pcf and 110 pcf, and strengths between 75 and 1,200 psi. It can be pervious or closed cell.

Due to the flowable, insulating properties, cellular concrete is excellent for backfilling sheet piles, MSE walls, bridge abutments, and soft areas where dynamic and lateral loading is important. It is the best material for slipline grouting, abandonments, void filling and slabjacking. The low-density also works well in cold regions when lifting slabs or filling voids to help insulate the ground.

We have 3 foam generators to produce stable pre-formed foam for all cellular applications and do our own field testing for density on every load for accuracy and to determine volume.

Remote is considered anywhere far enough away from our base that equipment, materials, and personnel individually or together have to be shipped in by truck, barge, ferry, or plane. As there are limited roads in the state, most shipping is by barge and plane.

Project areas around the state include Shemya, Adak, Atka, Dutch Harbor, False Pass, and Sand Point on the Aleutians, Wainwright, Barrow, and Deadhorse on the North Slope, Bethel, Platinum, Nikolai, Kaliganek, and New Stuyahok in Western Alaska, Circle, Fort Yukon, and Pogo Mine in the East, to Ketchikan, Wrangell, Petersburg, Sitka, Juneau, and Hoonah in Southeast.

Terry has 40 years of experience pumping concrete with boom pumps including Thomsen, Challenge, and Putzmeister, as well as many line pumps, including Challenge squeeze pumps and Mayco, Schwing, and Putzmeister swing-tube piston pumps.

We currently use four Putzmeister line pumps from the TK20 HP for compaction grouting and shotcrete to the TK70 for larger volume remote concrete projects. Many of the projects are in remote places and difficult to get to so the equipment has to be trucked, barged, or flown in. They also are often done in extreme winter conditions so equipment and lines have to enclosed and heated to keep from freezing. Custom fabricated picking elbows and tremie lines are made for underwater or deep injection applications.

Because of uncertain concrete materials in remote areas, pumping may be difficult or impossible. As I have extensive experience producing concrete, I can usually modify the mix design for pumpability.

Due to many years of remote concrete production, I know what the most cost effective and efficient method to get materials and equipment to most any remote location. Most of my projects are very difficult due to the location and/or characteristics of the job. One such project was coming up with the mix and method to plug the legs of a gas platform 160’ deep in Cook Inlet in 7 knott currents and 40 degree F water temperature. As there was only a 30-40 minute slack tide window every 6 hours for a diver to place up to 16 yards, there was no room for errors. A test batch with vma, plasticizer, and accelerator was successfully completed so that the mix set up in 1 hr without washing out at the bottom of Cook Inlet. A boom pump, 2 mixer trucks, admixes and super bags enough to batch over 100 yrds from Davis Block were mobilized to the Svenja and successfully placed in 5 days.

I work with local providers around the state for materials and/or equipment when possible, or supply what is needed. Many times I use the owner's or contractor's batch plant, trucks, or pump after making sure they are in good working order.

I am in the unique position of understanding the difficult logistics and realities of concrete production and QA/QC, as well as pumping in remote locations under extreme conditions.

Grouting Services

Compaction Grouting is the stabilization of poor soils under buildings, structures, roadbeds, railroads, or runways, by driving injection pipes down to stable ground and then injecting low-mobility grout to force out soft soils and replace with grout columns. Injeciton is continued in a pattern to cover all of the target area until the ground or building is raised back to original elevation. The amount of grout injected and pressures at each lift are closely monitored for quality control.

Filling voids or pipes can be as easy as plugging both ends of a pipe and filling with grout, or as complicated as figuring out the mix and method to inject grout 40' underground through a spring-loaded, expandable steel form with an inflatable plug to fill a void.

Bulkheading and the placement of fill and vent ports are important to make sure the voids are completely filled. Pipes with only one access point can also be filled with correctly placed fill and vent lines.

Custom grout designs are used to fill pipes down to 1" in diameter as well as pipes 3000' long. Cellular grout is often used for its ability to to flow long distances through small openings with low pressure. Cellular, at densities half that of other fill materials, also works excellent under settled abutments, buildings, or areas where weight is an issue.

Slab jacking is the raising of sunken or settled concrete floors by drilling holes and Injecting grout underneath.

Determining what caused the settlement is important to determine the best method for a long term fix. Small test holes are drilled to find out the size of the voids and stability of soil underneath so that an accurate estimate can made. The same holes can also be used as vent holes when grouting. Custom packers are inserted and low density, lightweight cellular grout is injected to fill the voids and stabilize the ground, then lift the slab back to an acceptable elevation. Most slabs can be raised by only 1 psi.

Cellular grout is most often used because it is flowable, half the weight of the existing ground, and also works well in cold regions as a good insulating fill but with structural strength.

With unstable soil underneath, compaction grouting is the best method to densify poor underlying soils to stabilize, and then raise the ground and slab.

Low-density cellular concrete, or grout is used to fill the annular space between an older damaged host pipe and a new plastic liner pipe, usually HDPE. The pipes can be for sewer lines, or culverts under roads or railroads. The grout density is usually kept between 40-55 pcf which is lighter than water so that the water-filled liner will not float. It also needs to be extremely flowable to keep injection pressure to a minimum, around 5 psi and travel long distances (800’) or very small spaces (1-2”) and still achieve 100-500 psi. QC is very critical on every load.

We use Putzmeister swing-tube line pumps as well as a small hand-carried piston pump along with gauges, packers and line from 2” to 4” to handle all of our grouting needs. All can be flown, trucked, or barged to job sites.

We use a two part polyurethane foam resin, heated, and injected under high pressure to fill voids and raise slabs. This works well for some applications but is limited in effectiveness and cost on many projects.

Means and methods for a variety of underground grouting applications including ground stabilization, building lifting, void filling, bulkheading pipes for abandonment or sliplining, as well as vent and fill port locations on pipes.