Highway Concrete Pavement Technology Development and Testing

Highway Concrete Pavement Technology Development and Testing
Author: Paul D. Krauss
Publisher:
Total Pages: 185
Release: 2006
Genre: Alkali-aggregate reactions
ISBN:

This study consists of continued field evaluations of treatments to four pavements suffering from distress due to alkali-silica reaction (ASR). One set of treatments was evaluated on existing pavements in Delaware, California, and Nevada that already showed ASR-related distress. Two of the existing pavements were located in relatively dry environments, while the third (in Delaware) was located in a moderately wet environment. The fourth site, in New Mexico, consisted of treatments on newly constructed pavements built with known reactive aggregates. At the Nevada site, the pavement was treated with methacrylate HMM), silane, linseed oil, or lithium hydroxide. The Delaware site used only lithium hydroxide, while the California site used only methacrylate. The test sections in New Mexico consisted of pavement that contained admixtures as ASR inhibitors. There were two rates of addition of lithium hydroxide, a 25 percent replacement of cement with combinations of Class C and F fly ashes, and a high-range water reducer (HRWR). This evaluation showed that, unfortunately, none of the treatments were significantly beneficial to pavements with moderate to advanced ASR damage. The methacrylate sealer was effective when applied to a bridge deck and extended the pavement service life 3 to 5 years or more when applied in two to three coats. The results indicate that, .regardless of the treatment, upward moisture migration from the subgrade to the bottom of the pavement is sufficient to support continued ASR even in dry desert climates. Preliminary results from the New Mexico test sites show that Class F ash, LOMAR :HRWA), or blended Class C and Class F ash may improve resistance to ASR distress. However, Class C ash can make deterioration much worse. Careful selection of the fly ash is necessary when attempting to mitigate known reactive aggregate. Continued monitoring of this test site is recommended.

Handbook for the Identification of Alkali-silica Reactivity in Highway Structures

Handbook for the Identification of Alkali-silica Reactivity in Highway Structures
Author: David Stark
Publisher:
Total Pages: 60
Release: 1991
Genre: Aggregates (Building materials)
ISBN:

This handbook is designed to help highway engineers and bridge inspectors spot and fix this very damaging and difficult-to-detect problem, namely, alkali-silica reactivity (ASR). The 49-page handbook provides for the field identification of ASR in portland cement concrete structures, such as highway pavements and bridges. ASR occurs when silica or silicates in aggregates react with alkali in the cement to form a gel-like substance which absorbs water and eventually cracks the concrete. Some areas of the country are more susceptible to this than others. Accurate detection of ASR is the key to choosing the best rehabilitation strategy. The proper diagnosis and assessment of the problem is covered.

An Evaluation of the SHRP Alkali-Silica Reactivity (Ars) Test

An Evaluation of the SHRP Alkali-Silica Reactivity (Ars) Test
Author: Mustaque Hossain
Publisher:
Total Pages: 36
Release: 1995
Genre: Aggregates (Building materials)
ISBN:

The objective of this research project was to evaluate the potential of the proposed Strategic Highway Research Program (SHRP) rapid immersion test covered by AASHTO TP 14 to determine alkali-silica reactivity (ASR) of Kansas aggregates using concrete beam samples. The TP 14 standard provides a proposed standard test method for accelerated detection of potentially deleterious expansion of mortar bars due to alkali-silica reaction. The mortar bars are cast and cured and the length measured as specified in the test procedure. The difference between the initial length of the specimen (at 24 hours after casting) and the length at each time period of measurement is calculated and expressed as the expansion in percent (of the original length).

Precast Concrete Pavement Technology

Precast Concrete Pavement Technology
Author: Shiraz D. Tayabji
Publisher:
Total Pages: 184
Release: 2013
Genre: Entrepreneurship
ISBN:

"TRB's second Strategic Highway Research Program (SHRP 2) Report S2-R05-RR-1: Precast Concrete Pavement Technology reviews the available precast concrete pavement (PCP) systems; summarizes PCP applications; and offers suggested guidelines for the design, fabrication, installation, and selection of PCP systems. " -- Publisher's description.

Alkali-silica Reactivity Potential and Mitigation

Alkali-silica Reactivity Potential and Mitigation
Author: Thano Drimalas
Publisher:
Total Pages: 0
Release: 2023
Genre:
ISBN: 9780309709255

"The realistic assessment of alkali-silica reactivity (ASR) and identification of appropriate preventive measures remain major challenges to the concrete and aggregate industry. Guidelines for estimating ASR potential are currently provided in AASHTO R 80 and ASTM C1778. However, since these guidelines are based on testing concrete mixtures with rather high cement and alkali contents, they may not properly apply to mixtures with moderate or low cement and alkali contents, which are generally used in highway construction. Including such mixtures in the development of the guidelines will make ASR assessment more realistic and the selection of mitigation measures more effective. NCHRP Research Report 1083: Alkali-Silica Reactivity Potential and Mitigation: Test Methods and State of Practice, from TRB's National Cooperative Highway Research Program, provides recommendations to improve currently used test methods for estimating ASR potential in concrete for highway construction."--Publisher's website