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):||5 May 2013|
|PDF File Size:||1.49 Mb|
|ePub File Size:||14.78 Mb|
|Price:||Free* [*Free Regsitration Required]|
Search Enter search terms: 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 cracks radiate from the interior of the aggregate out into the surrounding paste.
APPLICATION OF MODIFIED ASTM C1260 TEST FOR FLY ASH-CEMENT MIXTURES
Leave a Reply Cancel reply Your email address will not be published. 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. Specification of fineness and alkali content of cement, or both, might be beneficial to further improve the reliability and reproducibility of ASTM C That, honestly, is about as simple as I can explain this reaction.
This repository is part of the Iowa Research Commons.
When lithium, sodium or potassium lose their single outermost electron, they become positively charged. Signs of ASR are typically random map-cracking and spalled concrete. In addition to the standard 1 N NaOH solution, a 0. This test is similar to C with a testing period of 14 days. As stated earlier, many precasters will not have issues with ASR. Petrography may be used to classify an aggregate c126 potentially reactive, but expansion testing is required to determine the extent of the reactivity and appropriate levels of prevention.
The effects of clinker alkali content, aggregate reactivity, and sodium hydroxide NaOH solution concentration on the mortar expansion test results were also studied. In addition to discovering ASR, he was the first to explain that c11260 was negligible when the alkali content of the cement was below 0. Keep in mind that some cements contain a higher proportion of potassium sulfate K 2 SO 4 than sodium sulfate Na 2 SO 4. For precasters in identified ASR areas, the following methods for new concrete may be the most critical: At least, this was the blame at the time.
Stanton, began his research on a few of these structures and found an expansive reaction between cement and aggregate taking place. Photo c2160 by Frank Bowen. Skip to main content. Clinker alkali had no or little effect on moderately reactive aggregate; whereas it had considerable effect on highly reactive aggregate. You aastm just begun the journey into c12260 your own materials as they relate to ASR.
ASTM C Potential Alkali Reactivity of Aggregates | CTLGroup
Civil, Construction and Environmental Engineering Publications. Determined to understand more, I have spent the past several weeks diving into the mysteries of ASR using recent reports from the Federal Highway Administration and various other scholarly professionals in an effort to fill in the blanks. Great article that gives a simplified overview of ASR, expansion testing, and mitigation techniques. By Frank Bowen 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 this study, high and low alkali portland cement clinkers were selected and ground with gypsum in a laboratory ball mill to three fineness levels: Many consider C to be the best test method for evaluating deleterious ASR potential because it provides the strongest correlation to field performance.
Non-metal atoms gain an electron, or electrons, from another atom to become negatively charged ions. These empty voids, when created, allow the gel to migrate into the cracks. The same goes for calcium, but since it is in the second column of the periodic table, it must lose two electrons for this to happen. For ASR to occur, four things must be present: It is important to understand the benefits and deficiencies offered by various testing procedures.
This method is one of the best ways to see ASR happen if you intentionally use aggregates with a high silica content like glass in concrete. 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. Ions are atm charged particles formed when atoms lose or gain electrons.
When siliceous aggregate is attacked by an alkali solution, it is converted to a viscous alkali silicate gel. Atoms are comfortable with themselves when they are fully loaded on that outer band. Overall, ASR is characterized primarily by four main features: Ask c120 aggregate provider first for test results before contacting a laboratory.
If ASR has been identified by the specifying authority within the region, it is recommended that precast producers perform long-term testing on concrete samples.
This is a result of a number of sequential reactions. This test exposes specimens to a solution of sodium hydroxide NaOH.
What we do know, however, is important v1260 precasters to understand. Though Stanton might not have been the first to visually recognize ASR, he is credited with the first serious research into why it occurred. However, some cases of concrete failure could not be attributed to either of these causes, prompting a deeper investigation. If you can read like a chemist, it looks like this: Alkali metals, for example, which are c2160 in the far left column of the periodic table, have a single electron in their outermost band.