II , for the evaluation of coarse aggregates. B 1 40 range of select subgrade 20 range of granular ' M 0 0. Gradation curves of OPSS Inmost routine laboratory investigations ofinterestto thesportsscientist, arterial blood sampling isimpractical and Both the microDeval and the freeze - thaw tests have good multilaboratory precision Performance of aggregates in granular Skip to content. Low-volume roads comprise, at one end of the spectrum, farm-to-market roads, roads in developing countries, northern roads, roads on aboriginal lands and parklands; and at the other end of the spectrum, heavy haul roads for mining, oil and gas, oil sands extraction, and forestry.
Low-Volume Road Engineering: Design, Construction, and Maintenance gives an international perspective to the engineering design of low-volume roads and their construction and maintenance. It is a single reference drawing from the dispersed literature. It lays out the basic principles of each topic, from road location and geometric design, pavement design, slope stability and erosion control, through construction to maintenance, then refers the reader to more comprehensive treatment elsewhere.
Agencies may also have their own specific requirements based on local experience or material availability. Aggregate is usually described as either coarse aggregate retained 4. Aggregates generally make up about 95 percent of the total mass of hot-mix asphalt mixtures and 80 percent by mass of concrete - aggregate properties are, therefore, critical for quality hot-mix asphalt or concrete.
Typically, hot-mix asphalt mixtures consist of 50 percent coarse aggregate and 50 percent fine aggregate, whereas conventional concrete and concrete products typically require about 55 percent coarse aggregate and 45 percent fine aggregate. Crushed stone and processed sand and gravel are interchangeable for many applications, but not all.
The most important specification parameters are particle size and distribution, particle shape and texture, and physical and chemical properties to assess aggregate strength and durability. The gradation of the aggregates used in bituminous and concrete materials is very important to developing the required engineering properties of the materials and for economical production. Specifications generally permit a fairly broad range in gradation gradation band but a high degree of consistency is required during production for mix quality and uniformity.
In concrete, the colour and texture of the finished product is also largely a function of the aggregate and, particularly, the fine aggregate. The proportion of fine material produced in an aggregate operation depends on several factors, including the deposit geology and degree of crushing. In fine aggregates, the gradation is one of the most important quality factors. If it is controlled, the material is usually acceptable. However, it must be noted that more recent specifications, including the MTO special provisions and Superpave mix design method, place greater emphasis on the physical properties of fine aggregate, including micro-Deval abrasion and angularity.
In coarse aggregate, the desired gradation can generally be controlled by appropriate processing screening and the degree of crushing, but many physical and chemical properties must also be satisfied. Various deleterious materials, such as chert, shale and siltstone, may be present in a pit or quarry face, which may restrict or totally preclude the use of such materials.
Aggregate properties considerations in the assessment of aggregate construction purposes with example test methods include the following:. Please contact MTO.
Library ontario. If you would like to borrow from the physical collection please contact your local library to arrange for an Inter-Library Loan ILL. For more details please contact MTO. MTO Research Library online catalogue. MTO library online catalogue Publications in PDF are attached to the catalogue record, look for the paperclip icon and click on it to view the document.
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