Aggregate Quality Requirements for Pavements (2018) / Chapter Skim
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44 4.1 Introduction This chapter presents information related to the procedures used by transportation agencies to approve or certify aggregate sources. Agencies often consider various criteria or guidelines to allow a certain type of aggregate source to be used in construction of a specific pavement layer.
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Procedures for Approving Aggregate Sources 45 specific state quality requirements shall be tested to qualify for the surface course use for gravel roads (FHWA 2015)
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46 Aggregate Quality Requirements for Pavements Those agencies that indicated that they used Preapproval Option A or B or Approval by Agency Lab (see Figure 4-1) were asked to report how often they performed the approval process.
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Procedures for Approving Aggregate Sources 47 are not approved for usage (Indiana DOT 2017a)
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Procedures for Approving Aggregate Sources 49 presents a summary of the different aggregate classes and the physical property and quality requirements for different aggregate materials. Limits and physical properties are included for gravel, crushed stone, crushed concrete aggregate, slag materials, and other types of aggregates.
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50 Aggregate Quality Requirements for Pavements and the geological origin, and the fifth class (Class R) is for recycled concrete aggregates.
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Procedures for Approving Aggregate Sources 51 for low-volume and secondary roads (Iowa DOT 2017)
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52 Aggregate Quality Requirements for Pavements Participating transportation agencies reported the required quality classes for fine and coarse virgin aggregates, RAP, RCA, SFS, and BFS used for construction of asphalt surface treatment. The results are summarized in Table 4-10.
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Procedures for Approving Aggregate Sources 53 deleterious substances for each quality class were previously listed in Table 3-8 (AASHTO 2015)
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54 Aggregate Quality Requirements for Pavements summarized in Table 4-14. Note that the description for each aggregate quality class can be found in the relevant links to agency specifications presented in Appendix D
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Procedures for Approving Aggregate Sources 55 compliance to certain operational criteria, property ranges, and contract compliance for the sand equivalent, durability index, and R-value tests. Caltrans requires that the durability tests be conducted on the untreated aggregates for eligibility of use in treated base applications.
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56 Aggregate Quality Requirements for Pavements Texas DOT and Washington State DOT allow a maximum of 20% RAP by weight in unbound aggregate bases. Texas DOT allows up to 50% RAP by weight in cement-treated base layers.
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Procedures for Approving Aggregate Sources 57 weight deflectometer deflections on top of the drainage layers. These were typically 19 mils for the unstabilized aggregates and 13 mils for the cement-stabilized open-graded drainage layers (Kazmierowski et al.
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58 Aggregate Quality Requirements for Pavements 4.4.8 Filter Material for PCC Pavements Permeable subbases are generally constructed as the foundation of concrete pavements by using crushed aggregates with reduced amount of fines. They are often constructed where previous experience has indicated pavement faulting and pumping are observed distresses of concern.
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