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 Fastway plants for remote projects with local aggregates, accessible by road, barge, or ferry.

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.

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.

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.

Due to many years of remote concrete production, Terry knows 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 because of the location and/or characteristics of the job. We work with local providers around the state for materials and/or equipment when possible, or supply what is needed. Many times we use the owner's or contractor's batch plant, trucks, or pump and help get them in good working order. Terry can also train local personnel to run the equipment.

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 densify soft soils and form grout columns. Injection is continued in a pattern to cover all of the target area until the ground, building, or slab is raised back to original elevation, eliminating all voids. The amount of grout injected and pressures at each lift are closely monitored on every hole to adjust for differing soil conditions 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.

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.

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 the same Putzmeister swing-tube line pumps for grouting as well as concrete. The difference for most applications is that we slow down the pumps to a minimum output. For underground grouting the volume measurements are in cu ft per min and with the TK20 we can pump down to 1 cu ft per min at 2000 psi line pressure. That is important for densifying deep soils and lifting heavy structures and buildings.

For small projects that are very difficult or costly to ship large pumps to we use a small hand-carried piston pump powered by a hydraulic power pack.

Polyurethane expanding foam can be used to fill voids and lift slab sections in some cases. There are many suppliers and many different types to do similar things. 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.