|Standards for Concrete Silicate Treatments Under Way |
A task group of ASTM Committee C09 on Concrete and Concrete Aggregates welcomes stakeholders to develop standards characterizing the effects of silicate treatments on concrete. The committee seeks the consensus of all interested parties including personnel from the test-labs of material producers, independents, and government agencies.
The task group will develop standard performance specifications, mortar test specimens, application procedures, and end-product property measurements. Several preliminary rounds of testing have been completed, says Ben E. Edwards, Ph.D., the secretary of ASTM Subcommittee C09.22 on Materials Applied to Fresh Concrete. Ultimately we will produce a set of performance tests that will define a class of specification products.
Solutions of sodium silicate and other silicates have been used in connection with concrete substrates for many years, but despite a variety of claims by producers or distributors of these products, no generally accepted test methods for evaluating their effects are available, says Edwards, the chief chemist for BEE Laboratory, Blowing Rock, N.C. In some cases, applications of silicate may be deleterious to the concrete, such as their use as curing compounds without supplemental curing methods. It has been established that silicate solutions do not perform as liquid membrane-forming curing compounds (ASTM C 309, Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete), and do not adequately reduce water loss as tested by ASTM C 156, Standard Test Method for Water Retention by Concrete Curing Materials. However, other types of applications positively affect the properties of the final product. Confusion and disagreement between producers, specifiers and users is widespread. The proposed standards will allow specifiers to call for products that can be expected to deliver the particular properties of interest without relying simply on manufacturers claims.
To participate or obtain further technical information, contact Ben E. Edwards, Ph.D., BEE Laboratory, Blowing Rock, N.C. (phone: 828/265-2530). Committee C09 meets Dec. 8-11 in Miami Beach, Fla. For membership or meeting details, contact Jim Olshefsky, director, Committee Services, ASTM International (phone: 610/832-9714). //
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