.Section 4126. Aggregate for Polymer-Modified Microsurfacing
Crushed stone. For non-Interstate mixes steel slag may also be used.
For quartzite, granite, and slag meet requirements for Gradation No. 37 of the Aggregate Gradation Table, Article 4109.02. For limestone and dolomite meet requirements for Gradation No. 38 of the Aggregate Gradation Table, Article 4109.02.
Meet requirements of Table 4126.03-1 and 4126.03-2 with the exception that use of Friction Type 2 crushed stone requires a maximum abrasion loss of 30% and sand equivalence of not less than 60. Testing is based on aggregate crushed to 3/4 inch nominal size.
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Table 4126.03-1: Aggregate Quality |
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Aggregate Quality |
Maximum Percent Allowed |
Test Method |
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Abrasion |
40 |
AASHTO T 96 |
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A Freeze |
10 |
Office of Materials Test Method No. Iowa 211, Method A |
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Alumina(a) |
0.7 |
Office of Materials Test Method No. Iowa 222 |
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Sand Equivalence |
45 (Minimum) |
AASHTO T 176 |
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Organic Materials |
0.01 |
Office of Materials Test Method No. Iowa 215 |
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(a) If the Alumina value fails, determine the A Freeze value for specification compliance. Office of Materials Test Method No. Iowa 222 does not apply to gravel or quartzite. |
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Table 4126.03-02: Maximum Permissible Amounts of Objectionable Material |
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Objectionable Materials |
Maximum Percent Allowed |
Test Method |
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Unsound chert particles retained on No. 4 sieve |
0.5 |
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Total of all unsound chert, shale, coal, and iron combined |
1.0 |
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Clay Lumps/Friable Particles |
0.5 |
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Organic Materials, except coal |
0.1 |
Iowa DOT Materials Laboratory Test Method No. 215 |