Traditionally, base course aggregate mixtures have been designed using larger aggregate size than surface course aggregate mixturesthe maximum aggregate size had tended to be in the range 0. Recent research at the university of illinois 1 11 21 1 4 2 1 1 0 5 10 15 20 25 n um be r o f a ge nc ie s maximum allowable aggregate particle size figure 10 base layer densegraded unbound aggregate. Aggregates are the most mined materials in the world. Using electrical properties to classify the strength. No payment will be made for quantities of bituminous aggregate base course in excess of the quantity calculated from plan lines and dimensions. The percentage composition by weight of class 1, class 2, and class 3 aggregate. The standard testing procedure for this is the american society of testing.
The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. Provide densegraded aggregate 21a, 21aa, 22a, 23a, or salvaged aggregate for temporary maintenance gravel. Sub grade preparation 1 foreman 1 laboratory technician 2 laborers item 200. Payment will be made at the contract unit price for. It is located under the surface layer consisting of the wearing course and sometimes an extra binder course if there is a subbase course, the base course is. Those particles that are predominantly retained on the 4. Where not indicated, compacted thickness shall be 6 inches. It includes gravel, crushed rock, sand, recycled concrete, slag, and synthetic aggregate. Aggregate base course shall be applied over the prepared sub grade or sub base and compacted in accordance with section 26 of the caltrans standard specifications. Electronic copies of this book can be obtained via the internet at. Aggregates are coarse particulate rocklike material consisting of a collection of particles ranging in size from 50 mm. Wbdg is a gateway to uptodate information on integrated whole building design techniques and technologies. Fine aggregate consists of natural sand, manufactured sand, or a combination. Aggregate base is a construction aggregate typically composed of crushed rock capable of passing through a 20 millimetres 3.
Sieve analysis of fine and coarse aggregate dotd designation. The engineer will measure maintenance gravel, lm based on hauling unit dimensions and load count, before placement and compaction. Trbs national cooperative highway research program nchrp synthesis 445. Recycled aggregate is defined as aggregate resulting from the processing of inorganic or mineral material previously used in construction bs en 12620, 20. Minimum 75% by mass weight of the material coarser than the no. Ufgs 32 11 23 aggregate base course wbdg whole building. This product has reinforcing steel removed and pieces no larger than. As base course lies close under the pavement surface it is subjected to severe loading. When used in the base or subbase, they may be suitable for all types of traffic. Typical road structure cross section sub grade, base. Chapter 1 introduction the national academies press. High strength and elasticity are desirable in aggregate base and surface courses. Aggregate base course class 6 is one of seven classes of unbound aggregate bases that may be used. To see the results of all tests, click on the search button without specifying a company or quarry.
Aggregate base course definition of aggregate base. T89, standard specification for determining the liquid limit of soils. The base course or basecourse in pavements is a layer of material in an asphalt roadway, race. Coarse aggregate is also described by its bulk density, which is a property that can easily be tested in the laboratory. Consider the differences and similarities between the classes of the following objects. The design should be done so that to meet the above requirements for considerable number of years need proper design and construction supervision. A foundation or footing course, as the lowest course in a. Heat a viscous bituminous binder to make it fluid, then in a plant mix it with heated. The composition by weight of aggregate for the grading selected shall conform to table 2004. Use the table provided to document any pertinent information. Before constructing the base, complete a control strip to determine the level of compaction necessary to achieve the target density for the remaining base course. Refer to your agencys standard specifications regarding aggregate properties. Section 301 aggregate subbase, base courses, and base course material preconstruction establish line, stationing, and blue top for finish grade.
Chapter three granular base and subbase construction practices. The aggregates shall meet the requirements of subsection 703. Pdf effect of matric suction on resilient modulus of. Use the drop down boxes to select the company andor quarry submitting the sample.
While this could make excellent base gravel, it would likely perform poorly if used as gravel surfacing. Provide aggregate 21a, 21aa, or 22a if the plans show aggregate surface course later receiving a paved surface. Pdf on jan 1, 2007, greg arnold and others published the effect of grading on the. Materials specified for use in the construction of sub base and base courses for flexible and rigid pavements include the following. The goal of whole building design is to create a successful highperformance building by applying an integrated design and team approach to the project during the.
The effects of aggregate type, size, and content on the behavior of normal and highstrength concrete, and the relationships between compressive strength, flexural strength, and fracture energy are discussed. Chapter 3 division 300 bases section 301 through 303 vacant section 304 aggregate base and subbase course 304. In both aggregation and composition object of one class owns object of. Read chapter chapter two aggregate types and material selection. Pdf the effect of grading on the performance of basecourse. Aggregate base course article about aggregate base. Class 6 aggregate base course 34 roadbase class 6 aggregate base course is 100% post consumer concrete and meets or exceeds the colorado department of transportation cdot specifications. Aggregate base materials may be measured by the ton, cubic yard or square yard. Composition on mix design top 1 stability 2 skid resistance 3 durability. Construction aggregate, or simply aggregate, is a broad category of coarse to mediumgrained particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Materials specified for use in the construction of subbase and base courses for flexible and rigid pavements include the following. Sample size 2 kg or less, readability and sensitivity to 0. When it is necessary to blend two or more materials, each. Bases and subbases for concrete pavements aashto classification a6 or a7 soil groups or the unified soil classification system ch, mh, and oh soils.
The maximum compacted thickness of any one 1 layer shall not exceed six 6 inches. Embankment 1 foreman 1 laboratory technician 4 laborers item 105. Special provision ddot lid project version 4 aggregate base course for permeable pavement and bioretention 022820 page 2 of 6 2. Section 301 aggregate subbase, base courses, and base. Preferred aggregate base courses for lowvolume roads. Conform to a closer control meeting the tolerance requirements as specified in section 401. The concrete mixtures incorporate either basalt or crushed limestone, aggregate sizes of 12 mm h in. Typical road structure cross section sub grade, base course. There would be too much large stone resulting in very difficult blade maintenance. As defined by the astm international in astm d8, an aggregate is a a granular material of min eral composition such as sand, gravel, shell, slag, or crushed stone, used with a cementing medium to form mortars or concrete, or alone as in base courses, railroad ballasts, etc. Aggregates are a component of composite materials such as concrete and asphalt concrete. Aggregate is a granular material, such as sand, gravel, crushed stone, crushed hydrauliccement concrete, or iron blastfurnace slag, used with a hydraulic cementing medium to produce either concrete or mortar. Base course the lowest course on a masonry wall or pier, may also be part of the footing. This 2010 edition of the west virginia division of highways standard specifications, roads and bridges, has been issued with the intent for use on all projects in which bids are received after november 1, 2010.
There are several reasons for specifying grading limits and nominal maximum aggregate size. Abc class 6 is the prevalent base type that is used through out the state. Pavement meeting all the requirements above have been product if six distinctly different construction processes as follows. These qualities minimize the rate of disi ntegration and maximize the stability of the compacted material. If there is a subbase course, the base course is constructed directly above this layer. Avoid contamination with nonconcrete materials, including joint sealants, hma patching, and base layer aggregate or soil, when processing crushed concrete coarse aggregate. Where it is planned that the soil aggregate surface course is to be maintained for several years without bituminous surface treatment, the engineer should. Construction rock class 6 aggregate base course 34 roadbase class 6 aggregate base course is 100% post consumer concrete and meets or exceeds the colorado department of transportation cdot specifications.
The aggregate base course shall be constructed to the width and section sho wn in the drawings. The question what is the difference between association, aggregation, and composition has been frequently asked lately. Specifications include the allowable gradation ranges, as well as materials quality test requirements. Aggregation and composition are subsets of association meaning they are specific cases of association. Section 38 provides the quality requirements for surface and base course aggregates. Item unit description 301 cubic yard inch bituminous aggregate base item 302 asphalt concrete 302.
Gradation use base course where confined under a seal coat or pavement 29% fines. The percentage composition shall be determined by california test 202, modified by california test 105 when there is a difference in specific gravity of 0. Strength is a measure of the ability of an aggregate particle to stand up to pulling or crushing forces. Physical properties of aggregates rowan university. Aggregate base course definition of aggregate base course. In designated concrete rc2025 to rc4050, rca can automatically be used at 20% of coarse aggregate mpa, 2011. This section covers the requirements for the characteristics, source, supply and storage of sub base and base course pavement materials b. Effect of matric suction on resilient modulus of compacted aggregate base courses article pdf available in geotechnical and geological engineering 315 october 20 with 724 reads. Section includes specifications for aggregate base courses.
Cold mix surface courses are suitable for light and medium traffic. Specifications for aggregate bases are specified in section 703. If the required compacted depth of base course exceeds six 6 inches, the base shall be constructed in two 2 or more layers of approximate equal thickness. The base course requires 100% of the material to pass a 1 inch sieve, but allows up to 20% of the stone to be retained on the 34 inch sieve. Other factors responsible for non uniform foundation include variability due to a number of reasons including, natural causes, excavation and. This work may also be done by the contractor in certain circumstances. The material can be made of virgin newly mined rock, or of recycled asphalt and concrete.
Use surface course aggregate where placed directly on the road surface 615% fines. Recycled aggregate an overview sciencedirect topics. Section 301 aggregate subbase, base courses, and base course. Aggregate base ab is typically made of a recipe of mixing different sizes of crushed. Surface aggregate differs from base aggregate in two fundamental ways. Verify that planned depths are in agreement with the final surfacing section. American society for testing and materials astm international. The component particles will vary in size from 20 mm down to dust. Aggregate base course shall have minimum uniform thickness after compaction of dimensions indicated. September 30, 2011 aggregate base courses section 02310 aggregate base courses part 1 general 1.
It is located under the surface layer consisting of the wearing course and sometimes an extra binder course. Where it is planned that the soil aggregate surface course is to be. Aggregate is a granular material, such as sand, gravel, crushed stone, crushed hydrauliccement concrete, or iron blast. Hma 19m64 base course 3 binder grade 4 location within the payment 1 nominal maximum aggregate size mm superpave mix selection 4. Foreword this 2010 edition of the west virginia division of highways standard specifications, roads and bridges, has been issued with the intent. Aggregate sub base course 1 foreman 1 laboratory technician 4 laborers note. Practices for unbound aggregate pavement layers 20.
Range of particle sizes found in aggregate for use in concrete. Typical values substance specific gravity density lbft3 water 1. Acceptance will be based on random samples taken from each lift. Provide aggregate 23a if the plans show construction of aggregate surface without a paved surface. Long term performance of gravel base course layers in asphalt. Construct additional control strips whenever a change is made in the source, gradation, type of subgrade, type of base aggregate, layer thickness, or as the engineer requires. Sponsoring agency name and address texas department of transportation. Aggregate base course synonyms, aggregate base course pronunciation, aggregate base course translation, english dictionary definition of aggregate base course. The first or lower course of a foundation wall, made of large stones or a mass of concrete. Aggregates types of aggregates coarse aggregate, fine. Chapter 14 aggregates page 77 calculate cumulative percentage passing for the blended aggregate according the formula.
When consisting mainly of crushed concrete, it may be classified as recycled concrete aggregate rca. It is the layer immediately under the wearing surface applies whether the wearing surface is bituminous or cement concrete and or more inch thick or is but a thin bituminous layer. Aggregate for class 1, class 2, and class 3 aggregate subbases shall be clean and free from vegetable matter and other deleterious substances, and shall be of such composition that it can be compacted readily under watering and rolling to form a firm, stable base. The goal of whole building design is to create a successful highperformance building by applying an integrated design and team approach to the project during the planning and programming phases. D421 standard practice for dry preparation of soil samples for. Unbound aggregate base layers support traffic loads from the asphalt concrete surface layer and. This method of test is used to determine the particle size distribution of aggregates by dry sieving only. T27, standard method of test for sieve analysis of fine and coarse. The thicknesses and ages of the pavement and base course aggregate layers are shown in table 1. Physical properties of aggregates 54 aggregate tests consensus properties required source properties optional aggregate criteria based on aggregate blend based on traffic and depth into pavement design aggregate structure 0. Chapter two aggregate types and material selection practices.
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