Limerock Bearing Ratio Technician Training Course

Transcription

1 Limerock Bearing Ratio Technician Training Course Module 2: Equipment LBR Technician Release 10, Module The equipment section of this training will cover equipment referenced in AASHTO T 180, FM 1-T 180 and FM The appropriate test methods should be consulted for the most up-to-date requirements of all equipment. The requirements in this training course may not be updated as quickly as the prescribed methods. Always refer to the most recent version of the testing method in which the equipment is addressed. - will provide an overview of the equipment being used. This training will not cover each piece of equipment in depth but will provide the important requirements and considerations. 2 1

2 Equipment: Preparation Drying Oven: Maximum 140 F for drying, 230 ± 9 F for moisture content analysis Balances: Class G 5 and G 2 (AASHTO M 231) Sieves: 2 inch, 0.75 inch, No. 4 (conforming to AASHTO M 92) Jaw Crusher: Minimum 2.25 x 3.5 inch plates, 3/4 inch maximum opening (1/8 inch under tolerance) LBR Technician Release 10, Module Requirements for the following equipment found in AASHTO T : - Drying Oven Section 8.2, Section Balances Section Sieves Section Mixing Tools Section Containers Section Requirements for the following equipment found in FM 1-T 180 May 2017 revision: - Jaw Crusher Section

3 Equipment: Compaction Molds: Conforms to AAHSTO T 180 except 6.00 ± inch tall, ± ft3 volume, baseplate has 28 open holes 0.06 ± 0.03 inches in diameter. Volume of sample shall be within 1.2% of ft3. Spacer Disk: ± inch diameter, 1.41 ± inch tall Compaction Rammer (Manual, Automatic): ± 0.02 lbs, ± 0.06 inch drop, sector faced LBR Technician Release 10, Module 2 3 Requirements for the following equipment found in AASHTO T AND FM 1 T 180: Molds AASHTO Sections 3.1, Section 3.1.2, FM 1 T 180 Section 7.1 Molds should be replaced when they fall outside the dimension and volume requirements. If the mold falls outside the volume requirements (0.001 ft 3 = 1%) then the mold shall be replaced. New Molds: Perform volume verification by AASHTO T 19, Calibration of Measure to verify the true volume of the mold. In Service Molds: The technician can assume the sample volume to be ft 3 during testing as long as the mold remains within the tolerances outlined for volume, diameter, and height outlined in sections and Alternative mold assembles such as LBR or CBR molds, as allowed per AASHTO Note 2, shall be verified as outlined in section and of FM 1 T 180 Annual re verification of mold volume: Perform volume verification by calculating the volume of a cylinder (volume = pi(r 2 )*h) using the measured diameter and heights of the mold. Determine the sample volume by finding the surface area of the mold (mold volume / height (6 inches) and multiplying by the height of your sample (4.59 inches). The sample height should be within 1.2% of the standard volume ft 3. If the mold dimensions, volume, and calculated sample volume are within the tolerances the mold can be used and If the mold does not meet any of these tolerances it must be removed from service. Compaction Rammers Manual AASHTO Section 3.2.1, Automatic AASHTO Section 3.2.2, AASHTO Section 3.2.3, FM 1 T 180 Section

4 Equipment: Compaction Straightedge: minimum 10 inches in length, beveled edge Sieve: small enough for material to patch holes (i.e. #4 sieve) Moisture Containers Balances LBR Technician Release 10, Module Requirements for the following equipment found in AASHTO T AND FM 1- T 180: - Molds AASHTO Sections 3.1, Section 3.1.2, FM 1-T 180 Section Molds should be replaced when they fall outside the dimension and volume requirements. If the mold falls outside the volume requirements (0.001 ft 3 = 1%) then the mold shall be replaced. - New Molds: Perform volume verification by AASHTO T-19, Calibration of Measure to verify the true volume of the mold. - In-Service Molds: Perform volume verification by calculating the volume of a cylinder (volume = pi(r 2 )*h) using the measured diameter and heights of the mold. Determine the sample volume by finding the surface area of the mold (mold volume / height (6 inches) and multiplying by the height of your sample (4.59 inches). The sample height should be within 1.2% of the standard volume ft 3. If the mold dimensions, volume, and calculated sample volume are within the tolerances the mold can be used and the technician can assume the sample volume to be ft 3 during testing. If the mold does not meet any of these tolerances it must be removed from service. - Compaction Rammers Manual AASHTO Section 3.2.1, Automatic AASHTO Section 3.2.2, AASHTO Section 3.2.3, FM 1-T 180 Section

5 Equipment: Soaking and Draining Soaking Tank: maintains water level within 0.25 inches of the top of the soil Swell Plates: Perforated plate 2.5 ± 0.5 lbs Flat surface that allows free draining of the mold LBR Technician Release 10, Module Requirements for the following equipment found in FM 5-515: - Soaking Tank Section Swell Plates - Section

6 Equipment: Penetration Loading Device: can maintain 0.05 ± inch per minute Penetration Piston: ± inch diameter, minimum 5.00 inches long Surcharge Weights: One Annular Disc and several Slotted Discs weighing 5.00 ± 0.10 lbs Electronic Data Acquisition Device: Chart recorder or computer capable of producing load deflection curves LBR Technician Release 10, Module Requirements for the following equipment found in FM 5-515: - Loading Device Section Penetration Piston - Section Surcharge Weights - Section Electronic DAQ - Section

7 Equipment: Documentation All equipment shall be maintained and verified at a minimum of once every 12 months. All verifications should be documented showing compliance and documentation shall be maintained on site. LBR Technician Release 10, Module 2 7 Requirements for the following equipment found in FM 5-515: - Section 3.7: Documentation shall be maintained showing equipment verification at a frequency not to exceed 12 months. Verification documentation shall be maintained for the following equipment: Surcharge weights, penetration pistons, loading devices, swell plates, and jaw crushers. 2 7

8 Equipment: Quality and Process Control Maintenance and verification of equipment effects quality of the test results. There are numerous methods to ensuring quality results by process control: Daily cleaning and maintenance of equipment Regularly scheduled inspections of equipment used heavily Control Charts to track equipment tolerances between verification intervals It is recommended to have a device that provides a Process Control check on the consistency of the entire load frame system. The device should achieve an LBR value of 100 at the correct penetration. LBR Technician Release 10, Module Examples of Process Control Devices: Aggregate material that consistently produces the same LBR values, metal spring assemblies, hardened rubber block that does not deform after repetitive compression. 2 8

9 ANY QUESTIONS? LBR Technician Release 10, Module