1. TRADITIONAL LABORATORY TESTS
2. SPECIALIZED LABORATORY TESTS
PERMEABILITY TESTING ON UNDISTURBED SAMPLES
(Coming soon) Acquisition of a CU Triaxial Chamber scheduled for the year 2010. This equipment will allow MYV to perform ASTM D5084 (Standard Test Methods for Measurement of Hydraulic Conductivity on Saturated Porous Materials using a flexible wall permeameter).
COMPRESSIBILITY TESTING ON UNDISTURBED SAMPLE
(Coming soon) MYV recently acquired a pneumatic consolidometer Karol – Warner Conbel Type. The main advantage of this equipment is its accuracy thanks to the use of pneumatic loading steps (by compressed air) instead of the traditional oedometer device where weights are used to apply the stress to the specimen. The recently acquired oedometer allows to perform the following tests:
- ASTM D2435 (Standard Test Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading).
- ASTM D4829 (Standard Test Method for Expansion Index of Soils).
- ASTM D5333 (Standard Test Method for Measurement of Collapse Potential of Soils).
STRENGTH TESTING ON UNDISTURBED SAMPLE
(Coming soon) Acquisition of a CU Triaxial Chamber scheduled for the year 2010. This equipment will allow MYV to perform ASTM D4767 (Standard Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive Soils).
CHECKING SAMPLE DEGREE OF DISTURBANCE BY X - RAY
In critical projects, MYV follows the standard ASTM D4452 (Standard Practice for X-Ray Radiography of Soil Samples) in order to look for damage /disturbance on samples to be used for strength/deformability tests. If the sample presents some type of damage, it is advisable to get rid of it instead of using it in slow /expensive lab tests for meaningless results are to be expected. On the other hand, if the damage can be well located, the sample can be cut off in order to eliminate the damaged portion.
3. QUALITY CONTROL
Quality control of soil compaction
In the control of soil compaction, MYV uses the A PRIORI approach which consists in making decisions/corrections even before starting the compaction process in order to assure that the final product (compacted fill) meets the required standards.
In that sense, firstly, a careful moisture control is carried out by means of technologies like TDR (Time Domain Reflectometry) or ECHO (Capacitance-based device). Both technologies allow the user to determine the moisture content of the soils for fill in a matter of minutes. If the soil is either too dry or too wet in comparison to the optimum moisture content, corrective measures are immediately recommended by MYV personnel in order to achieve the proper moisture content to start compaction of the soil.
Once compaction starts on a given lift, MYV verifies the degree of improvement after each pass of the roller. This is possible by means of our CIH (Clegg Impact Hammer) that can obtain the CIV (Clegg Impact Value), parameter that is highly related to both the CBR value and the relative compaction percentage. The CIH offers the convenience of rapidly scanning compaction variations over large areas (at least one test per minute), thus helping to isolate problematic areas so that problems can be quickly addressed. In such cases, our personnel will show the contractor where the problems are and how to correct them.
Complementarily, MYV owns a DCP (Dynamic Cone Penetrometer) for compaction verification of existing fills with more than 1 meter in thickness. In contrast, CIH testing allows compaction verification of lifts no thicker than 25 – 30 cm. That is the reason why both DCP and CIH are complementary in nature. DCP allows the user to find loose / poorly compacted lifts hidden between well compacted lifts at depth into the fill. In this manner, DCP is an APOSTERIORI test that is able to detect problems in an existing fill (no thicker than 1 meter).
Quality Control of Fresh Concrete
Fabrication and Strength Testing of concrete cylinders. Slump measurement by the conventional method (Slump-Cone Test). Slump measurement by quick methods (K-Slump Tester). Performance follow-up of concrete production by means of state-of-the-art statistical techniques such like: SPC (Statistical Process Control), PWL (Percentage Within Limits) and CUSUM. MYV introduced in Costa Rica the use of the FCT (Fresh Concrete Tester) for rapid and simultaneous determination of important fresh concrete parameters like Temperature, Slump, water/cement ratio, and 28 day-potential-strength.
Quality Control of Hardened Concrete
Destructive testing of hardened concrete include: Coring and strength testing of concrete cores extracted from structural elements (beams, columns, slabs). Coring can be performed by means of our Core Drilling Machine, Milwaukee Type. Concrete cores can be extracted with diameter of either 4 inches or 6 inches, depending upon the drill bit to use. Non destructive testing of hardened concrete include: concrete test hammer (Schmidt Hammer) and SASW-S (Spectral Analysis of Surface Waves, structural version, see the corresponding section above).
MYV also owns the CTG – SASW which combines both Impact Echo and SASW techniques in order to provide a thorough survey of the hardened concrete quality (strength, thickness, and presence/condition of flaws)
4. INSPECTION DURING CONSTRUCTION
MYV is able to offer services of geotechnical follow-up as well as assessment of construction materials during the construction stage of a given project. Inspection services include the following: bearing capacity checks at footing bottom, assessment and performance follow-up of construction materials, suggestions and corrective measures when unexpected conditions are encountered, recommendations for temporary excavations, slope protection, erosion control, and the like.
In addition, MYV is able to design and execute Plate Load Tests, as well as Pile Load Tests and Micropile Load Tests. For the year 2010, MYV is planning to offer the following construction services: installation and reading of Osterberg Cells to measure friction capacity and point bearing capacity of drilled shafts and the corresponding load-displacement curves.
MYV owns a SE/IR equipment (Sonic Echo Impulse Response) to evaluate the integrity and determine the length of deep foundations, during construction stage. SE/IR tests can be performed on drilled shafts and driven or auger-cast piles. The test can also be performed on shallow wall structures such as an abutment or a wall pier of a bridge provided the top of the wall is accessible. Complementarily, MYV owns the SIR method (Slab Impulse Response) to evaluate the integrity of both slabs-on-grade and mat foundations.
Lastly, MYV acquired the Profometer Technology for detection and characterization of steel reinforcement: location, orientation, cover, and bar diameter, among others. This technology is highly useful for a Project Inspector whenever steel reinforcement must be checked in an already poured concrete element.