【国外标准】 Standard Test Methods for Determining the Chemical Resistance of Concrete Products to Acid Attack

4.1 As described in Guide C1894, the MICC is considered to be a three-stage process with the reduction in pH (Stage I) (for example, 12.5 > pH > 9-10), the establishment of biofilms which further lowers the pH (Stage II) (for example, 9-10 > pH > 4-6) and eventual deterioration due to biogenic acid exposure (Stage III) (for example, < ~4 pH). This document provides standard test methods to assess the effects of acid in Stage 3 for concrete.4.2 As described in Guide C1894, acid immersion testing should be used with great caution in specifying concrete as this is a final stage of deterioration and the concrete may not be exposed to the conditions of this test.4.3 The results obtained by these test methods should serve as a guide in, but not as the sole basis for, selection of a chemical-resistant material for a particular application. No attempt has been made to incorporate into this test method all the various factors that may affect the performance of a material when subjected to actual service.1.1 These test methods are intended to evaluate the chemical resistance of cement paste, mortar and concrete materials. This method is loosely based on Test Methods C267, however the solution is more rigorously defined and flexural strength is used. These test methods provide for the determination of changes in the following properties of the test specimens and test medium after exposure of the specimens to the medium:1.1.1 Mass of specimen,1.1.2 Appearance of specimen,1.1.3 Appearance of test medium, and1.1.4 Strength of specimens.1.2 Guide C1894 provides a standard guide for Microbially Induced Corrosion of Concrete (MICC) products. This standard is used for assessing the chemical resistance of cementitious products to acid attack caused by MICC; however as described in the guideline document for MICC products the current document only applies for Stage III of corrosion. This document is not intended to be a guideline document for the complete evaluation of MICC or for assessing the efficacy of antimicrobial additives used to reduce MICC.1.3 This standard supplements Test Methods C267 to improve the consistency of reported results for acids generated by MICC or other sources.1.4 This standard does not cover tests in which acidification is achieved by bacterial activity. Testing protocols for bacterial activity are described in Guide C1894.1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to alternative units (typically inch-pound units) that are provided for information only and are not considered standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.