This master should be used by designers working on Port of Portland construction projects and by designers working for PDX tenants (“Tenants”). Usage notes highlight a few specific editing choices, however the entire section should be evaluated and edited to fit specific project needs.

SECTION 321614 - CONCRETE MOW STRIP AND CONTROLLER BASE

PART 1 - GENERAL

1.1DESCRIPTION

  1. This section describes the construction of castinplace mow strip and irrigation controller bases.

1.2RELATED WORK SPECIFIED ELSEWHERE

  1. Section 031100, Concrete Formwork
  2. Section 032000, Concrete Reinforcement
  3. Section 033000, CastInPlace Concrete

1.3REFERENCES

  1. AASHTO: American Association of State Highway and Transportation Officials
  2. AASHTO T099: Standard Method of Test for Moisture-Density Relations of Soils Using a 2.5-kg (5.5-lb) Rammer and a 305-mm (12-in.) Drop
  3. AASHTO T180: Standard Method of Test for Moisture-Density Relations of Soils Using a 4.54-kg (10-lb) Rammer and a 457-mm (18-in.) Drop
  4. ASTM: American Society for Testing and Materials
  5. ASTM D698: Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12 400 ft-lbf/ft3 (600 kN-m/m3))

PART 2 - PRODUCTS

2.1CONCRETE

  1. CastInPlace Concrete Mow Strip: Conform to the requirements of Sections 031100, 032000, and 033000 for concrete Class 35003/4.
  2. Irrigation Controller Bases: Conform to the requirements of Section 033000 for concrete Class35003/4.

2.2EXPANSION MATERIAL

  1. Premolded, nonextruding filler material, 1/2inch minimum thickness.

2.3CURING COMPOUND

  1. Conform to the requirements of Section 033000.

2.4CRUSHED AGGREGATE

  1. Crushed aggregate shall be 3/4"0".

PART 3 - EXECUTION

3.1PREPARATION

  1. Compact subgrade to 92 percent of maximum density as measured by ASTM D698 (AASHTO T99), unless directed otherwise by the Port.
  2. Place aggregate base and compact to 95percent of the maximum density as measured by AASHTO T180.
  3. Immediately prior to placing the concrete, thoroughly wet the aggregate base to prevent moisture loss from the concrete mix to the subgrade.

3.2JOINTS IN MOWING STRIP

  1. Construct contraction joints of the weakenedplane type between expansion joints at intervals of no more than 20 feet. Form the contraction joints by grooving and inserting a preformed bituminous filler, or by other means approved by the Port. The top width of the joints shall not be less than 1/8 inch or greater than 1/4 inch. The joints shall penetrate 2 inches into the face and top surface of the mow strip.

3.3PLACEMENT AND FINISHING

  1. The concrete forms, if of wood, shall be sprayed, oiled, or otherwise covered with an impermeable membrane before use.
  2. Remove forms after the concrete has taken its initial set and while the concrete is still green. Repair minor defects with mortar containing one part portland cement and two parts sand. Plastering will not be permitted on the faces and exposed surfaces. Honeycombed and other structurally defective concrete shall be removed and replaced at no added cost to the Port. While the concrete is still green, finish the exposed surfaces by rubbing down high spots and form marks, by rubbing the moistened surfaces with a suitable device to provide a uniform texture and smooth surface, or by applying and rubbing a thin cement grout to produce a uniform color.
  3. Broom finish mow strip with strokes at right angles to length. Finish edges with 1/2inch radius edging tool, then broom over tool mark.
  4. Irrigation controller base shall be steeltrowelled, edge-tooled, and broom finished with a fine-haired broom parallel to the direction of the curb.
  5. After finishing has been completed, cover the concrete with an impermeable membrane or keep continuously wet until the concrete has reached a compressive strength of at least 2500psi.
  6. Surfaces from which forms are removed before the curing period has elapsed shall be protected and cured as specified for surfaces not covered by forms.

3.4TOLERANCES

  1. The finished mow strip and irrigation controller bases shall be within 1/4 inch, plus or minus, of finish grade and alignment.
  2. The exposed surfaces shall be brushfinished and shall be free of spalls, holes, rock pockets, or honeycomb and shall present a smooth, clean, and neat appearance.

END OF SECTION321614

11/17/2018 / CONCRETE MOW STRIP AND CONTROLLER BASE
S:\MASTERS\DIV-32\321614MT.DOC / 321614-1