Mobile laboratories are self-sufficient units set in box trucks, trailers, or recreation-type vehicles depending on the scope of testing to be performed and on the project site conditions. First designed and introduced by Twining Laboratories, mobile laboratories are now widely used in California for on-site testing of rapid strength concrete. They have serviced more than three hundred pavement replacement projects throughout the state and Twining is now collaborating with premier research centers to bring this innovative testing approach to other states. Rapid strength concrete, capable of achieving flexural strength of 400 psi or more in 1.5 to 4 hours after placement, is an ideal material for fast-track rehabilitation of pavements and construction of new pavements during short-time partial lane closures. Quality assurance requires testing of rapid strength concrete for flexural or compressive strength prior to opening lanes to traffic, and our mobile laboratories are ideal for this. Mobile laboratories designed and built for on-site testing of concrete, contain the following equipment and accessories:
- Compressive testing machine(s)
- Fixtures for flexural strength testing and compressive strength testing
- Calipers and micrometers for measuring specimens
- Thermometers and multi-channel temperature recorders for monitoring temperature of in-place concrete and test specimens
- Curing containers, thermal insulated containers for temperature-matching curing of cylinders for compressive strength, thermal insulated cover boxes for temperature-matching curing of beams for flexural strength, etc.
- Equipment for sampling concrete, fabricating test specimens and testing properties of fresh concrete
- Portable gasoline generators
- Stationary mounted water tanks with pumps
- Curing/storage devices for transferring specimens not tested in the field to a stationary or portable laboratory facility
Where required, concrete field testing can also be supplemented to test aggregates. Laboratories of this class use a larger vehicle. They also can be set in a separate vehicle or trailer, which allows us to locate such laboratories conveniently at the originating site of the of aggregate samples (concrete batch plants or quarries). Aggregate testing units are equipped with:
- Splitters for preparing aggregates for further testing in field conditions
- Portable mechanical and hand sieves
- Ovens for drying aggregates
- Washing devices
- Scales
- Special aggregate testing equipment as required
For projects where concrete specimens are required to be tested on-site after 28 days, Twining has designed portable laboratories that include curing units. Curing units are thermally insulated, air conditioned, steel portable containers. For curing cylinders, the container is provided with a fogging system and storage racks. The container for curing beams is equipped with lime-water curing tanks. Both types of containers can be used for initial and final curing of concrete specimens, according to ASTM C31 provisions. Storage capacity of a standard 40’ x 8′ portable curing unit is 350 beams. Storage capacity of a 20’x 8’ portable curing unit is 750 cylinders.