AASHTO R80-17 pdf free download

AASHTO R80-17 pdf free download.Determining the Reactivity of Concrete Aggregates and Selecting Appropriate Measures for Preventing| Deleterious Expansion in New Concrete Construction.
3. TERMINOLOGY
3.1. accelerated mortar-bar test (AMBT,)—test method used to determine aggregate reactivity (AASHTO T 303) or to evaluate the effectiveness of measures to prevent deleterious expansion when reactive aggregates are used (ASTM C 1567).
3.2. alkali—aggregate reaction (AAR)—chernical reaction in either mortar or concrete between alkalis (sodium and potassium) present in the concrete pore solution and certain constituents of some aggregates; under certain conditions, deleterious expansion of concrete or mortar may result. Two types of AAR are considered in this standard practice; these are alkali—carbonate reaction (ACR) and alkali—silica reaction (ASR).
3.3. alkali—carbonate reaction ‘AC’R,—the reaction between the alkalis (sodium and potassium) present in the concrete pore solution and certain carbonate rocks, particularly argillaceous calcitic dolomite and argillaceous dolomitic limestone, present in some aggregates; the products of the reaction may cause deleterious expansion and cracking of concrete.
3.4. alkali—silica reaction (ASR)—the reaction between the alkalis (sodium and potassium) present in the concrete pore solution and certain siliceous rocks or minerals, such as opaline chert, strained quartz, and acidic volcanic glass, present in significant quantities in some aggregates; the products of the reaction may cause deleterious expansion and cracking of concrete.
3.5. class of structure—in this guideline, structures are classified on the basis of the severity of the consequences should ASR occur.
3.6. concrete prism test (cPT,—test method (ASTM C 1293) used to determine aggregate reactivity or to evaluate the effectiveness of measures to prevent deleterious expansion when reactive aggregates are used. Another version of this test, ASTM Cl 105, can be used with a limited alkali content to determine the potential for alkali—carbonate reactivity.
3.7. deleterious expansion—an increase in volume that is sufficient to cause cracking of the concrete or result in other problems (e.g., misalignment of adjacent components, closing ofjoints. etc.).
3.8. deleteriously reactive—aggregates that undergo chemical reactions in concrete that subsequently result in deleterious expansion of the concrete.
3.9. equivalent alkali, Na2Oc—calculated from the sodium (Na20) and potassium oxide (K20) as follows: Na2Oe = Na20 + 0.658 x K20.
3.10. nondeleteriouslv reactive—aggregates with no reactive constituents or minor amounts of reactive constituents that may exhibit some small amount of reaction without producing significant damage to the concrete.
3.11. preventive measures—strategies for suppressing damaging expansion due to alkali—aggregate reaction (AAR).
3.1 2. supplenzentaiy cementitious material (‘SC’M,)—cementitious materials other than portland cement (i.e., pozzolans and slag).
4. SIGNIFICANCE AND USE
4.1. This practice describes a procedure for evaluating aggregate reactivity and determining measures to prevent deleterious expansion due to alkali—aggregate reaction (AAR).
4.2. Following this practice will not completely eliminate the possibility of deleterious expansion occurring in new construction; rather, the practice provides various approaches for minimizing the risk of AAR to a level acceptable to the owner.
4.3. Aggregate reactivity is determined on the basis of one or more of the following: field performance, petrographic examination, or the expansion testing of mortars or concrete, or both.
4.4. If the aggregate is deemed to be nondeleteriously reactive, it can be accepted for use in concrete with no further consideration of preventive measures (assuming that the physical properties of the aggregate render it suitable for use).
4.5. If the aggregate is found to he deleteriously reactive, it must then be determined whether the reaction is of the alkali—carbonate or alkali—silica type.AASHTO R80-17 pdf download.