Backed by quantifiable, ASTM standard research, pumice-blended cement will mitigate or eliminate alkali-silica reaction in curing concrete in the presence of even the most reactive aggregate.
Malad, Idaho (PRWEB) March 23, 2015
In regions with reactive aggregate, alkali-silica reaction (ASR) is a relentless concrete infrastructure assassin. If the seeds of ASR—reactive aggregate and Portland-cement spawned calcium hydroxide—are present in cured concrete, that concrete structure will not survive to the end of its engineered lifespan. There is no way to stop ASR once such chemically-flawed concrete is placed; no way to contain the slow-motion explosion that map-cracks the concrete—even the aggregate—and destroys its structural integrity.
The alkali-silica reaction must be defeated before it starts, and that means specifying a concrete mix design that includes a quantifiable ASR-mitigating supplementary cementing material (SCM). ASR mitigation can be done economically and consistently with a superior grade of carefully refined pumice, such as the Hess Pumice ASR Miti•GatorTM product.
This white paper briefly outlines the chemical mash up that spawns ASR and then examines the specific mechanisms by which pumice-blended cement both stomps the alkali-silica reaction and improves overall concrete performance.
Backed by quantifiable, ASTM standard research from two separate studies by the University of Utah, testing data detail how pumice-blended cement will mitigate or eliminate alkali-silica reaction in curing concrete in the presence of even the most reactive aggregate. And, as a percentage of cement replacement, it does so for pennies per yard.
The method by which pumice mitigates ASR also provides additional performance benefits to concrete in terms of strength and density. It works like this: pumice ignites a secondary pozzolanic reaction within curing concrete that consumes and chemically restructures a deleterious compound known as calcium hydroxide (CH). CH not only is a key player in the alkali-silica reaction, it is also responsible for a handful of other ills that plague modern concrete. When pumice is present in the concrete mix design, CH is significantly reduced. Without CH, the alkali-silica reaction is short-circuited. Without CH, the cured concrete matrix is more densely welded, which significantly amps resistance to sulfate and chloride attacks, increases resistance to freeze-thaw damage and abrasion, and provides impressive strength. As an SCM, pumice does all that consistently and predictably, pour after pour.