Section 4112. Intermediate Aggregate for Portland Cement Concrete
A. Crushed carbonate stone chips or pea gravel from approved sources as described in Materials I.M. 409.
B. For crushed limestone or dolomite chips, meet the durability class required for the coarse aggregate. Acquire uncrushed pea gravel from any PCC approved durability class gravel. When the gravel durability is lower than the coarse aggregate durability requirements, the pea gravel is not to exceed 15% of total aggregate in the mix.
Intermediate aggregate shall meet the requirements for gradation No. 2 of the Aggregate Gradation Table, Article 4109.02.
A. Intermediate Crushed Stone.
Meet the requirements of Table 4112.03-1:
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Table 4112.03-1: Aggregate Quality |
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Aggregate Quality |
Maximum Percent Allowed |
Test Method |
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Alumina(a) |
0.5 |
Office of Materials Test Method No. Iowa 222 |
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A Freeze |
6 |
Office of Materials Test Method No. Iowa 211, Method A |
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Clay Lumps and Friable Particles |
0.5 |
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(a) If the Alumina value fails, determine the A Freeze value for specification compliance. |
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Meet the requirements of Table 4112.03-2:
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Table 4112.03-2: Maximum Permissible Amounts of Objectionable Materials |
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Objectionable Materials. |
Maximum Percent Allowed |
Test Method |
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Coal and carbonaceous shale |
0.5 |
AASHTO T 113 |
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Total of all shale, similar objectionable materials, coal and iron combined |
1.0 |
AASHTO T 113 |
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Organic Materials, except coal |
0.01 |
Office of Materials Test Method No. Iowa 215 |
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Unsound chert particles retained on 3/8 inch sieve (Nonstructural concrete) |
3.0 |
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Unsound chert particles retained on 3/8 inch sieve (Structural concrete) |
2.0 |
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Note: Chert particle which break into three or more pieces when subjected to the freezing and thawing test will be considered unsound.
Chert in aggregate produced from limestone sources is defined as unsound when any of the fractions of the crushed or uncrushed chert do not meet the soundness requirements. |
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