Section 2: Laboratory Testing

Overview

To supplement field testing results, laboratory testing is required on samples properly acquired and retained from the drilling operations. This lab testing on soil and rock samples is used to correctly classify the material type and ascertain the nature, strength, and consolidation characteristics of the subsurface layers. Additional lab testing may be required at specific sites to determine swell potential, corrosion potential, permeability, and durability. Perform all laboratory testing in accordance with the relevant TxDOT, ASTM or AASHTO procedures.

Moisture Content Tests

Perform laboratory determination of moisture content in accordance with Tex-103-E, AASHTO T265 or ASTM D2216. Determine the moisture content at each geologic unit or stratum identified to establish the moisture profile at each boring.

Unit Weight

Perform unit weight of soils in accordance with ASTM D7263.

Grain Size Analysis and Passing No. 200 Sieve

Perform Particle Size Analysis of Soils in accordance with Tex-110-E, and Amount of Material in Soils Finer than the 75 micrometer (No. 200) Sieve in accordance with Tex-111-E.

Atterberg Limit Tests

Perform liquid limit, plastic limit, and plasticity index of soils in accordance with Tex-104-E, Tex-105-E, and Tex-106-E, or equivalent AASHTO or ASTM methods.

Unconfined Compressive Strength Tests and Unconsolidated, Undrained Triaxial Compression Tests

Perform unconfined compressive strength test in accordance with AASHTO T 208 or ASTM D2166.

Perform Unconsolidated, Undrained Triaxial compression test on cohesive soils in accordance with Tex118-E, or AASHTO T 296 or ASTM D2850.

Perform Unconfined Compressive Strength Tests and Unconsolidated, Undrained Triaxial Compression Tests on undisturbed 3-inch diameter specimens obtained in accordance with AASHTO T 207 or ASTM D1587.

Specimens shall be free from tailings, cuttings, seams, cracks, and/or other disturbance that may affect the strength result obtained. Do not use specimens with noticeable disturbance for testing. Do not use specimens obtained within the upper 6 inches of the thin-walled tube sampler for testing

Transport specimens for strength test to the laboratory and test as soon as practicable (after sampling) to prevent loss of moisture.

Consolidated Undrained Triaxial Compression Tests (CU testing)

Perform Consolidated Undrained (CU) triaxial tests accordance with Tex-131-E, or ASTM D4767. Perform CU on undisturbed 3-inch diameter specimens obtained in accordance with AASHTO T 207 or ASTM D1587. Specimens shall be free from tailings, cuttings, seams, cracks, and/or other disturbance that may affect the strength result obtained. Do not use specimens with noticeable disturbance for testing. Do not use specimens obtained within the upper 6 inches of the thin-walled tube sampler for testing.

Transport specimens for strength test to the laboratory and test as soon as practicable (after sampling) to prevent loss of moisture.

Direct Shear Tests

Perform Direct Shear testing under consolidated drained conditions in accordance with AASHTO T236 or ASTM D3080.

One Dimensional Consolidation Tests

Perform one-dimensional consolidation tests in accordance with AASHTO T216 or ASTM D2435.

One Dimensional Swell Tests

Perform one-dimensional swell tests in accordance with ASTM D4546.

Resistivity, pH, Sulfates and Chloride Ion Content in Soils

Perform soil resistivity tests in accordance with Tex-129-E, or AASHTO T288. Perform pH test of soils in accordance with Tex-128-E, or AASHTO T289. Perform water-soluble Sulfate Ion or Chloride Ion content in soils in accordance with Tex-620-J, or AASHTO T290 and AASHTO T291, respectively.

Organic Content

Perform soil organic content tests in accordance with AASHTO T267.