7-153 SECTIO N 780 – REPAI R MATERIALS 780.0 1 CONCRET E REPAI R MATERIALS . Concrete repair material shall be a prepackaged material and shall be one of the products listed on the Agency’s Approved Products List .
a.Concrete Repair Material, Type I . Type I concrete repair material shall be evaluated in accordance with the AASHTO Product Evaluation & Audit Solutions work plan for Evaluation of Rapid Set Concrete Patching Materials for Portland Cement Concrete , be a neat (having less than 5% aggregate retained on the 3/8 inch (9.50 mm ) sieve) overhead and vertical repair material, and meet the following requirements:
1.Compressive Strength . The neat material shall have a minimum 7 -day compressive strength of 2,000 psi and a minimum 28 -day compressive strength of 4,000 psi as determin ed in accordance with AASHTO T 106 .
2.Bond Strength by Direct Tension . The material shall have a minimum bond strength of 150 psi as determined in accordance with ASTM C1583 at 28 days, or sooner.
3.Freeze -Thaw Durability . The material shall have a min imum durability factor of 80, after 300 cycles, as determined in accordance with AASHTO T 161, Procedure A .
4.Length Change . The material shall meet the performance requirements of ASTM C928 as determined in accordance with AASHTO T 160 .
5.Chloride Ion Penetration . The material shall exhibit a chloride ion penetrability of Low, or less, as determined in accordance with AASHTO T 277 or AASHTO T 358 at 28 days, or sooner .
b.Concrete Repair Material, Type II . Type II concrete repair material shall be evaluated in accordance with the AASHTO Product Evaluation & Audit Solutions work plan for Evaluation of Rapid Set Concrete Patching Materials for Portland Cement Concrete , be a horizontal rapid setting repair material, and meet the requirements of Subsection 780.01(a) except as modified below .
1.Compressive Strength . The neat material shall have a minimum 3 -hour compressive strength of 1,200 psi and a minimum 7 -day compres sive strength of 5,000 psi as determined in accordance with AASHTO T 106 . 7-154 (c) Concrete Repair Material, Type III . Type III concrete repair material shall be evaluated in accordance with the AASHTO Product Evaluation & Audit Solutions work plan for Evaluation of Rapid Set Concrete Patching Materials for Portland Cement Concrete , be a horizontal rapid setting repair material, and meet the requirements of Subsection 780.01(a) except as modified below .
1.Compressive Strength . The neat material shall have a minimum 3 -hour compressive strength of 1,200 psi, a minimum 1 -day compressive strength of 2,900 psi, and a minimum 7-day compressive strength of 5,000 psi as determined in accordance with AASHTO T 22 .
2.Aggregate . The material shall contain greater than 5% coarse aggregate (aggregate contained on the 3/8 inch (9.50 mm) sieve). Coarse aggregate may be contained in the prepackaged material (extended), or material of the type and quantity specified by the manufacture r may be added to the prepackaged material (extendable).
d.Concrete Repair Material, Type IV . Type IV concrete repair material shall be an overhead, vertical, or horizontal polymer repair material meeting the following requirements:
1.Compressive Stre ngth. The neat material shall have a minimum 3 -hour compressive strength of 1,200 psi and a minimum 7 -day compressive strength of 5,000 psi as determined in accordance with ASTM C579 .
2.Bond Strength by Direct Tension . The material shall have a minimum b ond strength of 150 psi as determined in accordance with ASTM C1583 at 28 days, or sooner.
3.Linear Shrinkage . The material shall have a maximum linear shrinkage of 0.15% as determined in accordance with ASTM C531 .
4.Chloride Ion Penetration . The mater ial shall exhibit a chloride ion penetrability of Low, or less, as determined in accordance with AASHTO T 277 at 28 days, or sooner . 7-155 SECTION 781 – RAILROAD CROSSING MATERIALS
781.01 PRECAST CONCRETE GRADE CROSSING SYSTEMS . Precast concrete grade crossing
systems shall consist of concrete, bar reinforcement, steel angle, rubber rail seal, fasteners, hardware, and all other components required for the system. Systems shall be one of the systems listed on the Agency’s Approved Products List .
781.02 RUBBER RAIL SEAL . Rubber rail seal shall be a single high quality, homogenous elastomeric
compound that is ultraviolet , ozone, weathering, and chemical resistant. The compound shall not permanently deform under loading and shall be f ree of porosity, defects, and dimensional irregularities. Seals shall be designed for the use between the field and gage sides of the rail and the adjacent pavement. The seal shall provide vibration dampening and protection from thermal expansion and contr action and shall allow for normal rail deflection without transferring force to the roadway pavement. Seals shall be in accordance with the Americans with Disabilities Act.
781.03 Automatic Highway Crossing Warning System (Ahcws) .
a.Crossing Lamp Controller Units .
1.General Requirements . Crossing lamp controller units shall be a solid -state interface between the train detection unit and the flasher crossing warning lamps.
2.Hardware Design . Crossing lamp controllers shall be designed for mounting in a B1 type relay base and installed in the relay rack.
3.Operation .
a.Lamp driver circuits shall be capable of sinking up to 20 amps continuously from the flasher crossing warning lamps. Alternate flashing lamp and bell outputs shall energize no more than 1.0 second after control inputs a re de -energized.
b.The alternate lamp flashing rate shall be 55 pulses per minute (± 20%).
c.Where gate control is not provided, flashing lamp and bell outputs shall de -energize no more than 1.0 seconds after the control unit is energized.
d.Flashing an d steady lamp voltages shall remain within 2% of preset levels under normal conditions.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 1305–1306 of 1,380.