Furthermore, KAc may induce alkali-silica reaction in the concrete-containing reactive aggregate
, which causes expansion and cracks after a long-term contact.
ASTM C 1260 standard is used as industry standard for identifying the reactive aggregate
. This method does not well estimate the aggregate combinations with cementitious materials and the environment of aggregates used in such combinations.
Researchers found that NIRAS measurements do not appear to be affected by the reactive aggregate
size and show potential to evaluate job-specific aggregates, while also eliminating the need for the time-consuming crushing and grading processes.
As the reaction's name implies, the reactive aggregate
The results obtained by means of the chemical method in accordance with the ASTM C 289 place opal and granite in the field of potentially reactive aggregate
, while the results for quartzite and hornstone demonstrate that these are irreactive aggregates (Fig 1).
The goal of this project is to provide guidance to those states that want to use RCA that contains potentially reactive aggregate
. At least one state highway agency (SHA) has established a policy of mandatory recycling of any construction material within the zone of the construction contract.
Besides covering problems such as reactive aggregate
, wet/dry cycling and expansive soils, Bradley said the standards also would discuss surrounding landscapes.
Difference manifestations of the alkali-silica reaction in concrete according to the reaction kinetics of the reactive aggregate
. Cement and Concrete Research 36 11481156.
However, cracking was still apparent surrounding the edges of the prisms for the mixtures incorporating the reactive aggregate
(see Figure 5) indicating there still exists a large potential for ASR reactivity.
Test results showed that although cores had reactive aggregates
, yet no major ASR problem was observed (WAPDA, 2004).
Petrographic identification of alkali-silica reactive aggregates
in concrete from 20th century bridges.