International Concrete Abstracts Portal

The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

Showing 1-5 of 90 Abstracts search results

Document: 

CI4407Q&A

Date: 

July 1, 2022

Publication:

Concrete International

Volume:

44

Issue:

7

Abstract:

This month’s Q&A features a discussion on moisture in concrete slabs-on-ground. It focuses on water migration; pH on slab surfaces; efflorescence; vapor retarders/barriers; slab curling; moisture in slabs; concrete exposure to water, sulfates, freezing and thawing, and chlorides; admixtures to stop vapor transmission; and concrete moisture and flooring installation.


Document: 

CI4308Klinger

Date: 

August 1, 2021

Author(s):

James Klinger, Colin L. Lobo, and Bruce A. Suprenant

Publication:

Concrete International

Volume:

43

Issue:

8

Abstract:

Can vapor retarders protect concrete slabs-on-ground from sulfate attack? The authors believe they can. To support this claim, the article discusses durability requirements in ACI 318, as well as exposure requirements in other industry standards and reports, and provides test data from evaluations of systems for isolating concrete from aggressive environments, a contractor- sponsored study, and a manufacturer-sponsored study.


Document: 

CI4305ConcreteQ&A

Date: 

May 1, 2021

Publication:

Concrete International

Volume:

43

Issue:

5

Abstract:

This month’s Q&A discusses moisture vapor protection for concrete slabs that will be covered with moisture sensitive flooring materials. It focuses on the water vapor movement through a concrete slab, potential ways of reducing the water vapor transmission rate, and means of selecting a viable moisture vapor mitigation option.


Document: 

SP-338_02

Date: 

March 1, 2020

Author(s):

Kenneth C. Hover

Publication:

Symposium Papers

Volume:

338

Abstract:

PCA researchers interested in the problem of evaporation of bleed water from concrete surfaces borrowed an equation developed by hydrologists to predict evaporation from Lake Hefner in Oklahoma. PCA’s graphical representation of that equation, subsequently modified to its present form by NRMCA, was later incorporated into multiple ACI documents, and is known by concrete technologists world-wide as the “Evaporation Rate Nomograph.” The most appropriate use of this formulation in concrete construction is to estimate the evaporative potential of atmospheric conditions (known as “evaporativity”). Since the difference between actual and estimated evaporation rate can be in the range of ± 40% of the estimate, best use of the equation as routinely applied is as a semi-quantitative guide to estimate risk of early drying and inform decisions about timing and conduct of concrete placing and finishing operations. Use of the “Nomograph” and related “Apps” in specifications is more problematic, however, given: 1.) the inherent uncertainty in its underlying equation, 2.) the difficulty in obtaining input data that appropriately characterize jobsite microclimate, and 3.) establishing a mixture-specific criterion for tolerable evaporation rate.

DOI:

10.14359/51724723


Document: 

SP-338_06

Date: 

March 1, 2020

Author(s):

Oscar R. Antommattei

Publication:

Symposium Papers

Volume:

338

Abstract:

During hot weather concreting, contractors have several options for dealing with slump loss and rapid drying of concrete surfaces. Limiting slump loss requires cooperation between the concrete producer and contractor, especially with respect to reducing truck waiting time. Several options for minimizing surface drying are compared, based on effectiveness and cost. Finally, providing for adequate initial curing of concrete test cylinders can reduce the possibility of schedule delays and increased costs related to low strength-test results.

DOI:

10.14359/51724727


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