ASTM C1260 PDF
This standard is issued under the fixed designation C ; the number immediately 1 This test method is under the jurisdiction of ASTM Committee C09 on. All the Controls products ASTM C standard. Enter now!. Originally approved in Last previous edition approved in as C – 05a. 2 For referenced ASTM standards, visit the ASTM website,
|Published (Last):||2 October 2006|
|PDF File Size:||10.59 Mb|
|ePub File Size:||3.71 Mb|
|Price:||Free* [*Free Regsitration Required]|
This test exposes specimens to a solution of sodium hydroxide NaOH. Consequently, the two tests are often run together. More than a century ago, it was noticed that concrete could deteriorate from seawater and freezing weather cycles.
Clinker alkali had no or little ast on moderately reactive aggregate; whereas it had considerable effect on highly reactive aggregate. Skip to main content. The same goes for calcium, but since it is in the second column of the periodic table, it must lose two electrons for aetm to happen.
When dealing with ASR, a process that takes place over decades, accelerated tests should be conducted with bias. The results show that mortar-bar expansion was promoted with increased cement fineness regardless of clinker alkali, aggregate reactivity, or soak solution normality.
What we do know, however, is important for precasters to understand. This repository is part of the Iowa Research Commons. However, this chemical approach, which alters the reaction gel to a less expansive nature, has us in what I feel to be the right direction. However, C takes one year to perform when evaluating aggregate reactivity, or two years when evaluating the efficacy of SCMs to mitigate deleterious expansion.
This new ASTM standard and related AASHTO provisional standard provides detailed protocols and guidelines using previous ASR testing data, petrography and historical performance to provide a prescriptive decision-making process for mitigation.
ASTM C, Test equipment Controls
Eventually, the tensile stresses caused by the increase in volume exceed the tensile strength of the concrete, causing cracks. A s I scrolled through the few articles and reports I have collected over the past decade regarding alkali-silica reactions, I began to realize I had developed an ignorance to this elusive subject. In addition to the standard 1 N NaOH solution, a 0.
Satm is used to test the reactivity potential of aggregates, while C includes the use of secondary cementitious materials within the mortar bar samples to c160 the effective reduction of ASR. Overall, ASR is characterized primarily by four main features: Although cement fineness and clinker alkali content did not affect the classification in terms of potential reactivity of the aggregates used in this study, they might change the classification for the aggregates near the boundary between reactive and nonreactive aggregates.
Petrography may be used to classify an aggregate as potentially reactive, but expansion testing is required to determine the extent of the reactivity and appropriate levels of prevention.
Signs of ASR are typically random map-cracking and spalled concrete. Specification of fineness and alkali content of asttm, or both, might be beneficial to further improve the reliability and reproducibility of ASTM C Many consider C to be the ast test method for evaluating deleterious ASR potential because it provides the strongest correlation to field performance.
This document is currently not available here. As stated earlier, many precasters will not have issues with ASR. This is a result of a number of sequential reactions.
Filling in the Blanks on Alkali-Silica Reaction
Ask your aggregate provider first for test results before contacting a laboratory. C120 you can read like a chemist, it looks like this: This test is similar to C with a testing period of 14 days. Development of a more economical and more abundant admixture may be the future for ASR mitigation. Frank Bowen, a Master Precaster graduate, received his M.
The alkali content of cement is not a significant factor in affecting the expansion. Non-metal atoms gain an electron, or electrons, from another atom to become negatively charged ions. Atoms are comfortable with themselves when they are fully loaded on that outer band.
Great article that gives a simplified overview of ASR, expansion testing, and mitigation techniques. A petrographic examination of aggregate will give a comprehensive description of the aggregate source and quantify the various rock and mineral constituents present.
“Effect of Portland Cement Fineness on ASTM C Expansion” by Faith Bektas, Kejin Wang et al.
Regardless, here is a list of key ASR points for precasters to know: It is important to understand the benefits and deficiencies astk by various testing procedures. When lithium, sodium adtm potassium lose their single outermost electron, they become positively charged. This makes them highly reactive. While the fundamental physical and chemical reactions remain poorly understood, it is well known that ASR destroys the durability of concrete and can cause serious maintenance and reconstruction costs.
Cement mill certificates contain information that can prove useful for tracking changes in your concrete and controlling variability in your mix design. That is, if you have questions about the durability of your concrete, save some samples cc1260 leave them exposed to the elements. Your email address will not be published. If you compare this with the composition of your aggregates, you should give yourself a pat on the back.
Publication Version Published Version.
Photo provided by Frank Bowen. Map cracking, also known as three-point cracking, can cause other issues as well, such as shrinkage.