for Highway Construction Page 187 of 71 5 SECTION 303 – AGGREGATE BASE
303.01 Description.
Provide, place, and construct 1 or more courses of aggregate on a prepared surface.
303.02 Materials.
Provide aggregate as specified in 703. The Department will accept the aggregate from the windrow or roadway. If purchased and stockpiled, acceptance will be at the crushing plant. The Contractor may use crushed glass in base. Uniformly blend the crushed glass with the aggregate. Ensure the glass -aggregate blend meets the aggregate gradation specified. The Contractor may use glass crushed to ¾ inch minus up to approximately 15 percent by weight of aggregate base . Place the glass -aggregate base material at least 1 foot below unpaved surfaces. The Contractor may use glass crushed to 5/16 inch minus up to approximately 15 percent by weight in aggregate base , with no restriction on location. Use the following standard methods for tests: Compaction Standard for Coarse Granular Materials by Use of the Vibratory Spring- load Compactor ......................................................... Idaho IT 74 In-Place Density and Moisture Content of Soil and Soil Aggregate by Nuclear Methods (Shallow Depth) ................................................. AASHTO T 310 Method B Instead of Idaho IT 74, if approved, the maximum dry density of aggregate base may be determined as follows: Moisture Density Relations of Soils ........................................................... AASHTO T 180 Method D Prepare and submit an Idaho IT 74 density curve or an AASHTO T 180 Method D moisture density curve for the aggregate base before placing. This testing is incidental .
303.03 Construction Require ments.
A.General. Do not exceed a maximum compacted thickness of 0.5 foot for each layer. Construct the base in 2 or more layers of approximate equal thickness if the required compacted thickness of the base exceeds 0.5 foot. The compacted t hickness of a single layer of the base may be increased to 0.8 foot when vibrating or other types of special compacting equipment are used with approval. After each layer has been spread, compact the layer for its full width. Continue compaction until at least 95 percent of the maximum dry density is attained. Determine the density of aggregate base in place in accordance with AASHTO T 310 Method B. Maintain the surface of each layer dur ing the compaction operations so a uniform texture is produced and the aggregate firmly keyed. Apply enough water uniformly over the base materials during compaction to ensure proper compaction is achieved. for Highway Construction Page 188 of 71 5 B. Aggregate Base Material in Stockpile . Provide aggregate base material in stockpiles at designated locations. Before stockpiling material, clear and smooth the stockpile site and obtain the Engineer’s approval. Provide stockpiles that are neat and regular in form and occupy as small an area as possible. Construct stockpiles by first distributing t he material to be stockpiled over the entire base and building upward in successive layers not more than 3 foot in depth. Do not end dump or conveyor stack materials over the sides of the stockpile.
C.Aggregate Base Material, Load, Haul, and Place. Load, haul, and place stockpiled aggregate from designated sources on the roadbed. Spread, process, distribute, shape, and compact as specifi ed in this section. The Department will spe cify the location and cost of the stockpiled aggregate.
303.04 Method of Measurement.
The Engineer will measure acceptably completed work as follows:
1.Aggregate base will be by the ton or cubic yard.
2.Aggregate base material stockpiled will be by the ton or cubic yard.
3.Aggregate base load, haul, and place by the ton or cubic yard. The Engineer will deduct the weight of water in excess of 7 percent of the weight of dry aggregate from the weight of the aggregate base.
303.05 Basis of Payment .
The Department will pay for accepted quantities as follows: ___ Aggregate Type __ Base ................................................................. Ton or CY ___ Aggregate Type __ Stockpile ........................................................... Ton or CY ___ Aggregate Type __ Load/Haul/Place ............................................... Ton or CY A separate pay ment will not be made for glass used in aggregate base . for Highway Construction Page 189 of 71 5 SECTION 304 – RECONDITIONING
304.01 Description.
Recondition the surface of an existing road, shape the shoulders, and dispose of surplus material.
304.02 Materials.
Not specified.
304.03 Construction Requirements.
Scarify the roadbed, including the shoulders to the depth and width specified. Pulverize the scarified material so 5 percent or less of this material, exclusive of gravel or stone, is retained on a 2 -inch sieve. Moisten and compact the pulverized material to the required density. Blade and water the surface, if directed, and continue blading and watering during the rolling operations. Satis factorily main tain the surface until the base or surface course has been placed. Apply additional water to prevent checking or raveling, if needed. Excavation and repair soft spots as specified in 205 .03.E .
304.04 Method of Measurement.
The Engineer will measure acceptably completed work as follows:
1.Reconditioning will be by the station or mile and will include blading of shoulders, scarifying and pulverizing of the existing roadbed, handling of existing asphalt mixtures, compaction of the roadbed, finishing of the surface, and maintenance of the completed surface.
2.At the Engineer’s request, randomly -selected empty transport ing vehicles may be w eighed on a local certified scale able to produce a scale ticket for the Engineer’s documentation and verification.
3.Water by the thousands of gallons (MG), where 1 MG equals 1,000 gallons, transported or conveyed by means of calibrated tanks or distributors or by means of accurate water meters. Only the water used in mixing materials or ordered to keep the surface moist will be measured for payment .
304.05 Basis of Payment .
The Department will pay for accepted quantities as follows: Pay Item Pay Unit Reconditioning ........................................................................................ Station or Mile Water for Reconditioning ........................................................................ MG Excavation of Soft Spots ......................................................................... CY Soft Spot Repair ..................................................................................... CY The Department will pay for removal and disposal of unsuitable material under excavation of soft spots. The Department will pay for backfill material used to replace unsuitable material under its respective item or as extra work (104.02) . The Department will not pay for the Contractor’s optional replacement material.
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 223–224 of 768.