1、 TS-1c MP 16-1 AASHTO Standard Specification for Reclaimed Concrete Aggregate (RCA) for Use as Coarse Aggregate in Hydraulic Cement Concrete AASHTO Designation: MP 16-13 1. SCOPE 1.1. This specification covers coarse aggregate derived from reclaimed concrete for use in hydraulic cement concrete. The
2、 specification is not intended for use when lightweight, high-density, or other specialty concrete applications are required. When aggregate materials are properly processed and manufactured to the requirements of this specification, combined and mixed in accordance with the appropriate requirements
3、, and placed, consolidated, and cured properly, a concrete structure of acceptable strength and durability can be produced. Introducing reclaimed concrete aggregate (RCA) into concrete, however, requires the use of quality control and quality assurance procedures to ensure that deleterious materials
4、 that might be present in the reclaimed concrete aggregate will not adversely impact the quality of the concrete product. 1.2. Best practice applications for using reclaimed concrete aggregate in concrete shall consist of concrete pavements, cement-treated base courses, sidewalks, median barriers, c
5、urbings, and other nonstructural applications. Note 1Caution should be exercised if reclaimed concrete aggregate is considered for use in structural applications. The presence of deleterious materials and the variability in the source concrete may produce inconstant volumetric properties and affect
6、the properties of the concrete produced. Two properties of concern include dimensional stability and creep. 1.3. Because reclaimed concrete aggregate is a recycled material, various state and local jurisdiction laws and regulations may be applicable. The user of this specification is cautioned to co
7、ntact state and local environmental and other local regulators to determine what requirements are appropriate. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 43, Sizes of Aggregate for Road and Bridge Construction M 80, Coarse Aggregate for Hydraulic Cement Concrete T 2, Sampling of Aggregates T 1
8、1, Materials Finer Than 75-m (No. 200) Sieve in Mineral Aggregates by Washing T 19M/T 19, Bulk Density (“Unit Weight”) and Voids in Aggregate T 27, Sieve Analysis of Fine and Coarse Aggregates T 85, Specific Gravity and Absorption of Coarse Aggregate T 96, Resistance to Degradation of Small-Size Coa
9、rse Aggregate by Abrasion and Impact in the Los Angeles Machine 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c MP 16-2 AASHTO T 103, Soundness of Aggregates by Freezing and Thawing T 104, Soundnes
10、s of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate T 112, Clay Lumps and Friable Particles in Aggregate T 113, Lightweight Pieces in Aggregate T 161, Resistance of Concrete to Rapid Freezing and Thawing T 260, Sampling and Testing for Chloride Ion in Concrete and Concrete Raw Materials T 3
11、03, Accelerated Detection of Potentially Deleterious Expansion of Mortar Bars Due to Alkali-Silica Reaction T 327, Resistance of Coarse Aggregate to Degradation by Abrasion in the Micro-Deval Apparatus 2.2. ASTM Standards: C 125, Standard Terminology Relating to Concrete and Concrete Aggregates C 22
12、7, Standard Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method) C 289, Standard Test Method for Potential Alkali-Silica Reactivity of Aggregates (Chemical Method) C 295/C 295M, Standard Guide for Petrographic Examination of Aggregates for Concrete C 342,
13、Standard Test Method for Potential Volume Change of Cement-Aggregate Combinations (Withdrawn 2001) C 586, Standard Test Method for Potential Alkali Reactivity of Carbonate Rocks as Concrete Aggregates (Rock-Cylinder Method) C 856, Standard Practice for Petrographic Examination of Hardened Concrete C
14、 1293, Standard Test Method for Determination of Length Change of Concrete Due to Alkali-Silica Reaction D 6928, Standard Test Method for Resistance of Coarse Aggregate to Degradation by Abrasion in the Micro-Deval Apparatus 3. TERMINOLOGY 3.1. The definitions of concrete and concrete aggregate term
15、s used in this specification are provided in ASTM C 125. The term “reclaimed concrete aggregate,” as used in this specification, shall mean coarse aggregate material derived from the crushing, processing, and classification of hydraulic cement concrete construction debris recovered from roadways, si
16、dewalks, buildings, bridges, and other sources. 4. ORDERING INFORMATION 4.1. The purchaser or specifier shall include the following information in the purchase order or contract documents: 4.1.1. Reference to this specification and year of issue, 4.1.2. Grading to be furnished (AASHTO Size No.) (Sec
17、tion 6.1), 4.1.3. Soundness testing requirement (Section 7.2), 4.1.4. Class designation of aggregate (Table 1), 2013 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c MP 16-3 AASHTO 4.1.5. Whether the res
18、triction on reactive materials applies (Section 7.3), 4.1.6. Additional testing requirements, and 4.1.7. Any exceptions or additions to this specification. 5. SAMPLING 5.1. Sample reclaimed concrete aggregate in accordance with T 2. 6. GRADING AND PROPORTIONS 6.1. Coarse reclaimed concrete aggregate
19、 tested in accordance with T 27 shall conform to the coarse aggregate gradation requirements prescribed in M 43 for the size number specified in the contract documents. Note 2Generally, there is no reason that reclaimed concrete aggregate should have gradation requirements that differ from natural o
20、r conventional aggregate materials. Note 3The ranges shown in M 43 are, by necessity, very wide in order to accommodate nationwide conditions. For quality control of any specific operation, a producer should develop an average gradation for the particular source and production facilities, and contro
21、l the gradation within reasonable tolerances from this average. Where coarse aggregate sizes numbers 357 or 467 are used, the aggregate should be furnished in at least two separate sizes. 7. PHYSICAL PROPERTIES 7.1. Reclaimed concrete aggregate shall have a maximum Los Angeles abrasion loss of 50 pe
22、rcent, measured in accordance with T 96. Note 4T 327, Micro-Deval, may be required in lieu of T 96 if the specifying agency has experience with the procedure and has established limits. 7.2. Reclaimed concrete aggregate soundness testing shall be conducted in accordance with T 104 at 5 cycles. The m
23、aximum limit for soundness shall be 12 percent if sodium sulfate is used and 18 percent if magnesium sulfate is used. Note 5Reclaimed concrete aggregate can be susceptible to sulfate attack when tested for soundness using sodium sulfate or magnesium sulfate solutions, resulting in higher than expect
24、ed soundness loss values (particularly when sodium sulfate solution is used in the test procedure). Sulfate solution test methods (T 104) should be applied if local experience has shown these methods to be acceptable; however, alternative approaches may be used. 7.3. Reclaimed concrete aggregate for
25、 use in concrete that will be subjected to in-service wetting, extended exposure to humid atmosphere, or contact with moist ground shall not contain any materials that are reactive with alkali components in the cement in an amount sufficient to cause excessive expansion of mortar or concrete. Except
26、, if such materials are present in injurious amounts, the coarse aggregate may be used with the addition of a material that has been shown to prevent harmful expansion due to the alkali-aggregate reaction. Alkali reactivity shall be tested in accordance with T 303 when alkali-silica reaction is susp
27、ected, in accordance with ASTM C 586 when alkali-carbonate reaction is suspected. Note 6If the source and history of the reclaimed concrete aggregate are known and no reactive failures were present in the source concrete, testing for reactive expansion may not be necessary. However, unless a precise
28、 history is known, the source concrete may have not been exposed to all elements required to cause reactive expansion, and the reclaimed concrete aggregate may be reactive. See Appendix X2 for a discussion of alternative test methods. Mitigation methods found 2013 by the American Association of Stat
29、e Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c MP 16-4 AASHTO to work with natural reactive aggregates may not be effective with potentially expansive RCA. Aggregate that gave satisfactory performance in the original concrete may not co
30、ntinue to do so when used as RCA in new concrete. Consider the contribution of alkali from the RCA in addition to the alkali from the new hydraulic cement. 7.4. Reclaimed concrete aggregate for use in concrete that will be subjected to freeze-thaw action shall not contain aggregate components that e
31、xpand and result in D-cracking of the concrete. When potential D-cracking is suspected, the reclaimed concrete aggregate shall be tested in accordance with T 161. Note 7In areas where D-cracking is a significant problem and agencies have developed equivalent test methods, local methods of testing ma
32、y be used. Acceptance criteria for T 161 and equivalent methods should be based on local criteria that have been developed to address the issue of D-cracking. 7.5. Reclaimed concrete aggregate shall meet the flat and elongated particle requirements of the specifying jurisdiction. 7.6. Reclaimed conc
33、rete aggregate shall be tested in accordance with T 85 to establish the specific gravity and absorption. For specific gravity, the total variability of tests from minimum value to maximum value shall not exceed 0.100; and for absorption, the total variability of tests from minimum value to maximum v
34、alue shall not exceed 0.8 percent. Aggregates that have specific gravity and absorption values that fall outside of these limits shall be stockpiled separately, and the limits stated above shall apply to the new stockpile. Note 8Testing of specific gravity and absorption may not be necessary during
35、production of aggregate if the reclaimed concrete is from one source with known aggregate properties. Note 9Coarse reclaimed concrete aggregate may contain air-entrained concrete mortar and, therefore, may be highly absorptive and can exhibit low and highly variable specific gravity values. Utilizin
36、g highly absorptive aggregates (coarse and fine) that do not exhibit consistent specific gravity values in hydraulic cement concrete can adversely affect the weighing and batching process in the concrete production operation. Further discussions of this issue are presented in Appendix X1. 8. DELETER
37、IOUS SUBSTANCES 8.1. Reclaimed concrete aggregate shall not contain clay lumps and friable particles, chert, coal and lignite, or other deleterious substances that exceed the maximum allowable amounts listed in Table 1 when tested in accordance with T 112, T 113, and ASTM C 295/C 295M. 2013 by the A
38、merican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-1c MP 16-5 AASHTO Table 1Limits for Deleterious Substances and Physical Property Requirements of Reclaimed Coarse Aggregate for Concrete Maximum Allowable PercentaCl
39、ass DesignationbClay Lumps and Friable Particles Chert (Less Than 2.40 sp gr SSD)cSum of Clay Lumps, Friable Particles, and Chert (Less Than 2.40 sp gr SSD)cOther Deleterious SubstancesdCoal and Lignite A 2.0 3.0 2.0 0.3 0.2 B 3.0 5.0 3.0 0.3 0.2 C 3.0 8.0 5.0 0.3 0.2 aThe engineer may supplement th
40、e requirements of Table 1 by placing limits on the amount of deleterious substances or physical properties in accordance with local experience and practice. bAggregate conforming to the requirements for the various classes designated in Table 1 should generally be suitable for the following uses: Ty
41、pical Uses (Suggested) Weathering Exposure Class of Aggregate Concrete pavements, cement-treated base courses, sidewalks, median barriers, curbings, and other non-structural applications Severe A Moderate B Negligible C The purchaser or specifier must indicate the class of aggregate to be furnished
42、as the degree of weathering exposure is not precisely defined. cThese limitations apply only to aggregate in which chert appears as an impurity. They are not applicable to gravels that are predominantly chert. Limitations on the soundness of such aggregate must be based on service records in the env
43、ironment in which it is used. dOther deleterious substances include adherent fines, vegetable matter, plastics, plaster, paper, gypsum board, metals, fabrics, wood, brick, tile, glass, and bituminous materials. The percentage of these materials shall be determined in accordance with ASTM C 295 or ot
44、her equivalent method approved by the specifying jurisdiction. Note 10The presence of deleterious materials in aggregates used in the production of hydraulic cement concrete could adversely affect concrete setting time, strength, or both, and could also induce expansive reactions that could result i
45、n premature deterioration of the concrete structure. As a result, strict quality control and quality assurance procedures are required to ensure that reclaimed concrete aggregate material used as coarse aggregate in the production of concrete will not adversely affect the quality of the concrete pro
46、duct. 8.2. Reclaimed concrete aggregate shall not contain more than 1.5 percent by mass of material finer than the 75-m (No. 200) sieve in accordance with T 11. 8.3. Reclaimed concrete aggregate, when sampled and tested according to T 260, shall not contain chloride ion in excess of 0.6 lb per cubic
47、 yard of concrete. 9. QUALITY CONTROL 9.1. If the contractor/supplier wishes to use reclaimed concrete aggregate, or combinations of reclaimed concrete aggregate and other approved aggregate materials, a request shall be made to the engineer for approval. The percentage of combined materials shall b
48、e established as part of a pre-submitted blended aggregate combination. At the engineers discretion, revised hydraulic cement concrete mix designs shall be required when percentages of materials change. Note 11A revised concrete mix design is recommended when percentages of materials change. The rec
49、laimed concrete aggregate will likely have a different specific gravity and absorption than the virgin aggregate. 9.2. The contractor/supplier of recycled concrete aggregate shall develop and implement a quality control plan for aggregate production. 9.2.1. The quality control plan shall detail the production procedures, testing methods, and testing frequencies that will be used to ensure that recycled concrete aggregate meets the requirements of this specification. 2013 by the American Association of State Highway and
