Accurate

Materials testing is a necessary step to constructing safe and durable structures. Our on-site inspection and laboratory testing services are designed to give you the information you need with the least impact on your schedule.

Whitaker Laboratory, Inc. engineers and technicians are accredited to perform construction materials testing by:

American Association of State Highway and Transportation Officials ( AASHTO)

American Concrete Institute ( ACI)

American Welding Society ( AWS)

Cement & Concrete Reference Laboratory ( CCRL)

Electronic Data Interchange (EDR)

American Association of State Highway and Transportation Officials ( AASHTO) American Concrete Institute ( ACI) American Welding Society ( AWS) Cement & Concrete Reference Laboratory ( CCRL) Electronic Data Interchange (EDR)

Georgia Department of Transportation (GA DOT)

Georgia Department of Natural Resources (GA DNR)

Environmental Protection Agency (EPA)

Georgia Soil & Water Conservation (GA SWCC)

Humboldt Scientific

International Code Council (ICC)

National Institute for Certification in Engineering Technologies (NICET)

Georgia Department of Transportation (GA DOT) Georgia Department of Natural Resources (GA DNR) Environmental Protection Agency (EPA) Georgia Soil & Water Conservation (GA SWCC) Humboldt Scientific International Code Council (ICC) National Institute for Certification in Engineering Technologies (NICET)

RADCO

South Carolina Department of Health and Environmental Control (SC DHEC)

South Carolina Department of Transportation (SC DOT)

Troxler

US Army Corp of Engineers

US Transportation Security Administration (US TSA)

RADCO South Carolina Department of Health and Environmental Control (SC DHEC) South Carolina Department of Transportation (SC DOT) Troxler US Army Corp of Engineers US Transportation Security Administration (US TSA)

Materials

Soil Testing

Certified soil testing methods:

  • Soil has been used in construction for all of human history. Through experience we have learned that compacting the soil offers many benefits including:

    1. Increasing bearing capacity

    2. Increasing stability

    3. Decreasing permeability

    4. Reducing heaving from freeze-thaw cycles

    5. Controlling erosion

    6. Reducing subsidence

  • Field density tests (FDT) confirm soil compaction which is essential to provide the strength and stability needed to support earthworks, structures and pavements. There are different methods including:

    1. Sand replacement

    2. Core cutter

    3. Water displacement

  • Soil consolidation testing predicts the soils ability to bear a load. When a load is first applied to soil, it is supported by a rapid increase of pore water pressure. Over time, this water pressure decreases as water drains away resulting in soil consolidation or soil settlement.

    The leaning tower of Pisa is an example of what can happen to a structure after the soil settles. Today, foundation soil is tested for compaction before construction begins, allowing for construction of taller and heavier buildings.

  • The unconfined compression test is a method of soil shear testing for cohesive soils such as clays or cemented soils only.

  • The Atterberg Limits tests were developed in 1911 and are used for fine-grained clay and silt soils.

    The tests determine the moisture content at which the soils transition between solid, semi-solid, plastic and liquid states. The changes between these stages are the Atterberg Limits and include the shrinkage limit, the plastic limit and the liquid limit.

    This test is used to predict how these soils might expand or shrink at different levels of load and moisture.

  • Soils are made up of grains of different shapes and sizes with each imparting different kinds of properties to the soil. To predict the properties of the soil the different sized grains are measured to evaluate mean size and size range of a sample.

    Investigating the properties of the soils determines if it is suitable to be used for concrete, road subsurface, building foundation or filler media.

  • A soil survey is a systematic approach to describing, classifying and mapping soils in a given area. Level III Soil Surveys are the minimum type of survey required to determine if a site is suited to an On-Site Sewage Management Systems (septic system) and for land sub-dividing. These soil surveys require a minimum of four borings for testing per one acre of land.

  • The results are used in pavement and foundation designs.

  • An infiltration test measures the speed with which water drains (percolates) through soil. Generally, sandy soil will absorb more water than soil with clay or soil where the water table is close to the surface.

    Percolation testing can be used to properly design and build a septic drain field (leach field) or infiltration basin and to predict how the soil behaves under moisture conditions.

  • The California Bearing Ratio (CBR) test was developed by the California state highway department in the 1930’s. The test evaluates the strength or bearing capacity of soil subgrades and base course materials for use in constructing highways, airport runways, parking lots and other pavements.

  • Specific gravity is the ratio of soil material density to the density of water. It is used to calculate soil density, void ratio and saturation.

    The test is used when designing structure foundations, calculating the stability of soil embankments, and predicting settlement of engineered soil fills.

  • When on-site soils are unsuitable for use in construction, one economic strategy is to amend the soil to meet the necessary requirements.

    After testing the properties of the on-site soils, engineers determine the correct mixture of on-site soil and/or aggregate, cement material, water and compaction needed to meet the projects strength and durability requirements.

    This process creates soil-cement, which is also known as cement-stabilized base, cement-treated soil, cement-treated aggregate base or “dirtcrete.”

astm qualified SOIL testING methods:

D421 Practice for Dry Preparation of Soil Samples for Particle-Size Analysis and Determination of Soil Constants

D422 Test Method for Particle-Size Analysis of Soils

D698 Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort

D1140 Test Methods for Amount of Material in Soils Finer than No. 200 (75-µm) Sieve

D1556 Test Method for Density and Unit Weight of Soil in Place by Sand-Cone Method

D1557 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort

D1883 Test Method for CBR (California Bearing Ratio) of Laboratory-Compacted Soils

D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass

D2419 Test Method for Sand Equivalent Value of Soils and Fine Aggregate

D2487 Practice for Classification of Soils for Engineering Purposes

D2488 Practice for Description and Identification of Soils

D4318 Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils

D6938 Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods

Concrete Testing

Certified CONCRETE testing methods:

  • A F-number is the metric used to describe the quality of concrete slab construction. F-numbers are created from several measurements which are put through a formula.

    A high Floor Flatness (FF) number equals flatter floors with less bumps or grooves.

    A high Floor Levelness (FL) number equals a level slab with less tilts or pitches.

  • Concrete compression-testing machines test the compressive strength of concrete cylinders by applying a continuous load until failure occurs.

  • A flexural test of concrete measures the tensile strength of the concrete indirectly by measuring the ability of a beam to withstand failure in bending.

    The test is useful to determine how much force it can withstand and is used for warehouse slabs, and interstate/airport pavements.

  • Concrete mix design is the science of specifying how much of each material is needed to balance cost, placement, strength, durability, density and appearance. Some of the questions that need to be answered are:

    1. Placement method

    2. Slump requirements

    3. Joint requirements

    4. Spacing of reinforcement

    5. Required strength

    An experienced lab will make trial batches and test performance of each mix before making a recommendation.

  • Core drilling concrete is needed to test the in-place strength of the concrete through core sample analyses and is also common when drilling to install recessed lighting, plumbing, HVAC, cabling, electrical and more utilities.

    Diamond core drills are the most effective tools to use as they cut through the aggregate particles as well as the concrete.

  • Slump tests measure concrete workability and consistency. Three layers of concrete are placed in a specifically shaped mold and compacted between each layer. After removing the mold, how the concrete reacts determines if it should be used and to what purpose.

  • Windsor probe testing provides an indication of the in-place strength of concrete by firing a steel probe into concrete using a powder-filled cartridge gun. The strength of the concrete is measured by the penetration depth reached by the probe.

    Swiss (Rebound) Hammer testing was developed in 1948 by a Swiss engineer named Ernst Schmidt utilizing the rebound principle. A steel hammer with a predetermined amount of energy impacts a steel plunger on the surface of the concrete. The distance that the hammer rebounds is an indication of the concretes compressive strength.

  • Per ASTM guidelines to confirm the concrete placed meets project specifications, samples must be taken from the ready-mix truck after 10% and before 90% of the load has been discharged.

    Test cylinder molds are cast to confirm the concrete placed meets the compressive strength specifications. Usually four (6x12) cylinder molds are cast with two tested in 7 days and two tested in 28 days.

  • Gravel, crusthed stone, sand, slag, recycled concrete and geosynthetic aggregates can be used in the production of concrete. These aggregates must undergo various tests to analyze their characteristics including strength and angularity, gradation, maximum size, unit weight, moisture and more. Each of these characteristics can affect the properties of the finished concrete. These tests will determine if the sample aggregates are appropriate to the mix design and meet the project specifications.

  • To perform a concrete penetration resistance test, a device is used to drive a small pin or probe into the surface of the concrete. The strength of the in-place concrete is then measured by the force used to penetrate and the depth reached.

  • As concrete slabs cure, excess water gradually evaporates from the surface of the slab first. Relative humidity tests using probes will involve drilling a hole into the concrete and inserting an electronic meter into it for 72 hours. The meter can then determine how much moisture is present through the core of the slab.

    Relative humidity moisture testing is necessary prior to installing moisture barriers, flooring finishes or additional flooring materials to prevent delamination of floor adhesive, blistering of epoxy coatings, re-emulsifications of the adhesive (stain), and curling, cracking or bubbling of the flooring materials.

astm qualified Concrete testing methods:

C31 Practice for Making and Curing Concrete Test Specimens in the Field

C39 Test Method for Compressive Strength of Cylindrical Concrete Specimens

C42 Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete

C78 Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)

C138 Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete

C143 Test Method for Slump of Hydraulic-Cement Concrete

C172 Practice for Sampling Freshly Mixed Concrete

C173 Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method

C192 Practice for Making and Curing Concrete Test Specimens in the Laboratory

C231 Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method

C617 Practice for Capping Cylindrical Concrete Specimens

C803 Test Method for Penetration Resistance of Hardened Concrete

C805 Test Method for Rebound Number of Hardened Concrete

C1064 Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete

C1231 Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders

Masonry Testing

Certified Masonry testing methods:

  • Two methods of testing mortar are typically used. Compressive strength of cubes and determining the aggregate ratio.

  • Masonry grout is used to fill the voids in masonry creating a single unit of the masonry, grout, reinforcements and mortar. Specific molds are then constructed to test for compression strength.

  • ASTM C140 testing methods and requirements are used for sampling and testing masonry units. These requirements include specific methods for:

    1. Sampling

    2. Measurement of dimensions

    3. Compressive strength

    4. Absorption

    5. Unit weight (density)

    6. Moisture content

    7. Fire rating

  • The unit strength method is based on the net area compressive strength of the unit and the type of mortar used.

  • Masonry prism sets are constructed by masons under the supervision of testing technicians. They must always be constructed in stack-bond configuration, have a full mortar bed and joints are always struck flush. The prisms are then moisture sealed on-site for 48 hours before being transported to the laboratory for testing.

    48 hours prior to the designated testing time, the prism is removed from the moisture sealed bag and capped with either a sulfur or high-strength gypsum compound to ensure a regular testing surface. The center mass of the prism is then aligned with the center thrust of the compression machine.

  • Our Windsor Pin system is a useful means of evaluating the in-place strength of historical mortars.

  • If conditions are not conducive to masonry removal and transport to the lab for testing, “in situ” or in-place testing can be performed. This is often chosen for historic buildings or structures over 100 years old.

  • Using ASTM C67 methods for sampling and testing brick units, the following tests can be performed:

    1. Modulus of rupture

    2. Compressive strength

    3. Absorption

    4. Saturation coefficient

    5. Effect of freezing and thawing

    6. Efflorescence

    7. Initial rate absorption

    8. Determining weight and size

astm qualified Masonry testing methods:

C67 Test Methods for Sampling and Testing Brick and Structural Clay Tile

C140 Test Methods for Sampling and Testing Concrete Masonry Units and Related Units

C780 Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry

C1019 Test Method for Sampling and Testing Grout

C1314 Test Method for Compressive Strength of Masonry Prisms

C1552 Practice for Capping Concrete Masonry Units, Related Units and Masonry Prisms for Compression Testing

Aggregate Testing

Certified Aggregate testing methods:

  • Construction mixes contain a binding agent, coarse aggregates (stones), fine aggregates (sand) and water. The binding agent ensures the materials are cohesive and the water used makes the mixture workable, but it is the aggregate properties that most influence compressive strength.

    Our lab performs a wide range of aggregate testing including:

    • Grading of fine aggregate

    • Grading of coarse aggregate

    • Organic impurities (fine aggregate)

    • Flat/elongated particle percentage

    • Chloride content

    • Sulphate content

    • Potential alkali-silica reactivity

    • Abrasion resistance

    • Elongation index

    • Specific gravity, water absorption

    • 10% fines value

    • Moisture content

    • Soundness

    • Point load test

    • Surface texture & weathering grade

    • Loose bulk density

    • Grading of aggregate base coarse materials (ABC)

    • Deleterious materials

    • Grading of filter materials

    • Splitting tensile strength for rock core

  • The Marshall Stability Test was discovered in 1939 by Bruce Marshall of the Mississippi Highway Department. The Marshall test allows engineers to identify the optimum asphalt mix for maximum strength and stability for the project specifications. The test includes:

    1. Aggregate selection

    2. Binder selection

    3. Sample preparation

    4. Stability testing

    5. Density and air void analysis

    Gyratory compacted specimens became a requirement when Superpave mixes were developed.

  • The American Concrete Institute defines aggregate as “granular material, such as sand, gravel, crushed stone, crushed hydraulic cement concrete, or iron blast-furnace slag, used with a cementing medium to produce either concrete or mortar.”

    With aggregates normally constituting 60% to 75% of the mix, poor selection or quality control can greatly affect the performance of the finished materials.

    Aggregate selection is based upon the following properties:

    1. Gradations

    2. Shapes

    3. Specific gravities

    These properties directly affect the finished materials in the following ways:

    1. Workability

    2. Air content

    3. Hardened properties

    4. Finish

    5. Density

    Once aggregates are chosen and sourced, batches of the mix design are created and tested to see if they meet product specifications such as:

    1. Compressive strength

    2. Air entrapment

    3. Absorption

    These specifications are commonly determined by testing slump, early strength and surface finish.

  • Concrete and mortar mixes contain the binding agent, coarse aggregates (stones), fine aggregates (sand) and water. The binding agent ensures the materials are cohesive and the water used makes the mixture workable, but it is the aggregate properties that most influence compressive strength.

    As the water evaporates during curing it leaves behind voids that can cause shrinkage and early cracking if it is not minimized by using a well-graded aggregate. There are four types of gradation (particle size distribution).

    1. Well-Graded means the sample possesses the required amount of each aggregate size and generally means a wide range of particles sizes are present.

    2. Gap-Graded means the sample possesses some but not all of the aggregate sizes and never preferred for construction mixes.

    3. Uniformly-Graded

    4. Poorly-Graded means the sample possesses aggregates of the same size, which would create spaces in the mix.

    To determine the gradation the aggregate is passed through progressively smaller sieves. The weights remaining in each sieve are recorded and the gradation curve can be calculated.

    Aggregate extraction refers to testing a concrete or mortar mixture that has already cured. The first step is to extract a sample, next the binder is often chemically removed, and finally the aggregate can be gradated as described above.

  • Diamond coring of a cured aggregate mixture is usually performed if signs of deterioration are observed or as part of ongoing quality control. After the sample is extracted it is tested for thickness and density.

astm qualified Aggregate testing methods:

C29 Test Method for Bulk Density (“Unit Weight) and Voids in Aggregate

C40 Test Method for Organic Impurities in Fine Aggregates for Concrete

C117 Test Method for Materials Finer than 75-µm (No. 200) Sieve in Mineral Aggregates by Washing

C127 Test Method for Density, Relative Density (Specific Gravity), and Absorption of Course Aggregate

C128 Test Method for Density, Relative Density (Specific Gravity), and Absorption of Fine Aggregate

C136 Test Method for Sieve Analysis of Fine and Course Aggregates

C566 Test Method for Total Evaporable Moisture Content of Aggregate by Drying

C702 Practice for Reducing Samples of Aggregate to Testing Size

D2419 Test Method for Sand Equivalent Value of Soils and Fine Aggregate

Asphalt Testing

astm qualified Asphalt testing methods:

D2041 Test Method for Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures

D2726 Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous Mixtures

D3203 Test Method for Percent Air Voids in Compacted Dense and Open Bituminous Paving Mixtures

D5444 Test Method for Mechanical Size Analysis of Extracted Aggregate

D6307 Test Method for Asphalt Content of Hot-Mix Asphalt by Ignition Method

D6926 Practice for Preparation of Bituminous Specimens Using Marshall Apparatus

D6927 Test Method for Marshall Stability and Flow of Bituminous Mixtures

Sprayed Fire-Resistive

astm qualified sprayed fire-resistive material test methods:

E605 Test Methods for Thickness and Density of Sprayed Fire-Resistive Material (SFRM) Applied to Structural Members

E736 Test Method for Cohesion/Adhesion of Sprayed Fire-Resistive Materials Applied to Structural Members

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