International Concrete Abstracts Portal

Showing 1-5 of 22 Abstracts search results

Document: 

23-288

Date: 

August 1, 2024

Author(s):

Deep Tripathi, Richard Morin, Mohamed Lamine Kateb, and Arezki Tagnit-Hamou

Publication:

Materials Journal

Volume:

121

Issue:

4

Abstract:

Ground-glass pozzolan has recently been considered a supplementary cementitious material by Canadian (CSA A3000) and American (ASTM C1866/C1866M) standards, but limited studies have been done on ground-glass use on-site. So, in this study, several sidewalk projects were performed by the SAQ Industrial Chair at the University of Sherbrooke from 2014 to 2017 on fields with different proportions of ground glass (that is, 10, 15, and 20%) in different conditions considered in such a cold climatic region. Sidewalks are a nonstructural plain concrete element that are among the most exposed to chloride and freezing and thawing in saturated conditions of municipal infrastructures. Coring campaigns were carried out on these concretes after several years of exposure (between 5 and 8 years). The results of core samples extracted from the sites were compared to the laboratory-cured samples taken during the casting. These laboratory concrete mixtures were tested for fresh, hardened (compressive strength), and durability (freezing and thawing, scaling resistance, chloride-ion penetrability, electrical resistivity, and drying shrinkage) properties (up to 1 year). The results show that ground-glass concrete performs very well at all cement replacements in all manners in terms of long-term performance. Besides that, using ground-glass pozzolan in field projects also decreases the carbon footprint and environmental and glass disposal problems.

DOI:

10.14359/51740781


Document: 

21-470

Date: 

January 1, 2023

Author(s):

Julie K. Buffenbarger, James M. Casilio, Hessam AzariJafari, and Stephen S. Szoke

Publication:

Materials Journal

Volume:

120

Issue:

1

Abstract:

The overdesign of concrete mixtures and substandard concrete acceptance testing practices significantly impact the concrete industry’s role in sustainable construction. This study evaluates the impact of overdesign on the sustainability of concrete and embodied carbon emissions at the national and project scales. In addition, this paper reviews quality results from a concrete producer survey; established industry standards and their role in acceptance testing in the building codes; the reliance on proper acceptance testing by the licensed design professional, building code official, and the project owner; and the carbon footprints that result from overdesign of concrete mixtures. In 2020, a field survey conducted on over 100 projects documented Pennsylvania’s quality of field testing. Of those surveyed, only 15% of the projects met the testing criteria within the ASTM and building code requirements. As a result, the total overdesign-induced cement consumption is as large as 6.7% of the estimated cement used in the United States.

DOI:

10.14359/51737334


Document: 

20-375

Date: 

September 1, 2021

Author(s):

Karthik H. Obla and Colin L. Lobo

Publication:

Materials Journal

Volume:

118

Issue:

5

Abstract:

The resistivity of concrete is gaining acceptance as an easier and more reliable method to measure the penetrability of water and dissolved chemicals into concrete. This study evaluates the surface and bulk resistivity of concrete specimens prepared from mixtures with varying levels of penetrability or transport properties. Test specimens were conditioned by different methods as permitted by the standards. In Part 1, the results indicate that, based on measured resistivity, concrete mixtures are classified for transport properties similar to ASTM C1202. Resistivity measurements were less variable. Changes in the resistivity of specimens placed in simulated service conditions for 1 year are also evaluated. Comparisons were also made on resistivity measured on smaller specimens obtained from different locations of a cylindrical specimen. In Part 2, the impact of various specimen conditioning techniques allowed by the standards on the degree of saturation, resistivity, and characterization of concrete for transport properties are discussed.

DOI:

10.14359/51732934


Document: 

20-079

Date: 

January 1, 2021

Author(s):

Prannoy Suraneni, Lisa Burris, Christopher R. Shearer, and R. Douglas Hooton

Publication:

Materials Journal

Volume:

118

Issue:

1

Abstract:

ASTM C618 and AASHTO M 295 specifications for fly ash represent the primary documents used by U.S. state and federal agencies to determine the suitability of a fly ash source for use in concrete. Other countries have broadly similar specifications for fly ash. The article compares specifications from the United States, Canada, Europe, Australia, and New Zealand, noting similarities and differences. Despite its common use, several criticisms of the ASTM C618 specification exist and are discussed in this document. Specifically, concerns exist regarding its dependence on strength activity index testing for determination of fly ash reactivity and strength generation potential, and loss on ignition for quantification of unburnt carbon content, as these tests relate somewhat poorly to performance of the fly ash in concrete. Recently developed test methods that could improve some of the most problematic components of the ASTM C618 specification are discussed.

DOI:

10.14359/51725994


Document: 

18-527

Date: 

January 1, 2020

Author(s):

Ahmed Abdulhaq Ahmed and David Trejo

Publication:

Materials Journal

Volume:

117

Issue:

1

Abstract:

ASTM C1152 is used to determine, in most cases, the total chloride concentration of hydraulic cement, mortar, or concrete systems. When these test standards were first developed, only ordinary portland cement (OPC) samples were evaluated. There is limited information on the test’s applicability to calcium aluminate cement (CAC) and calcium sulfoaluminate cement (CSA). The standard also requires manual titration, which is slow and costly. This study compares results using manual titration, as described in ASTM C1152, with results using auto-titration for OPC, CAC, and CSA. This study then investigates whether the ASTM C1152 procedure, modified using auto-titration, can be used to provide a reasonable estimate of total admixed chloride concentrations for the cementitious systems. Results indicate that there is no significant difference in results from manual and auto-titration for all systems. However, the results from the CSA indicate that acid-soluble extraction followed by auto-titration significantly underestimates the total admixed chloride concentration.

DOI:

10.14359/51720290


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