ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-5 of 151 Abstracts search results

Document: 

23-276

Date: 

March 15, 2024

Author(s):

Ashley S. Carey, Grayson B. Sisung, Isaac L. Howard, Brad Songer, Dylan A. Scott, and Jay Shannon

Publication:

Materials Journal

Abstract:

Determining in-place properties of mass concrete placements is elusive, and currently, there are minimal to no test methods available that are both predictive and a direct measurement of mechanical properties. This paper presents a three-stage testing framework that utilizes common laboratory equipment and laboratory scale specimens to quantify the thermal and mechanical properties of mass high-strength concrete placements. To evaluate this framework, four mass placement of varying sizes and insulations were cast where temperature histories were measured at several locations within each placement where maximum temperatures of 107 to 119°C were recorded. The laboratory curing protocols were then developed using this mass placement temperature data and the three-stage testing framework to cure laboratory specimens to represent each mass placement. Laboratory curing protocols developed for center and intermediate regions of the mass placements reasonably replicated thermal histories of the mass placements, while the first stage of the three-stage framework reasonably replicated temperatures near the edge of the mass placements. Additionally, there were statistically significant relationships detected between calibration variables used to develop laboratory curing protocols and measured compressive strength. Overall, the proposed three-stage testing framework is a measurable step towards creating a predictive laboratory curing protocol by accounting for the mixture characteristics of thermo-mechanical properties of high-strength concretes.

DOI:

10.14359/51740705


Document: 

22-206

Date: 

December 1, 2023

Author(s):

Rita Maria Ghantous, Margaret N. Goodwin, Mehdi Khanzadeh Moradllo, Sean Quinn, Vahit Aktan, O. Burkan Isgor, Steven Reese, and W. Jason Weiss

Publication:

Materials Journal

Volume:

120

Issue:

6

Abstract:

Carbonatable calcium silicate cement (CSC) is a promising approach to reducing the carbon footprint associated with concrete production. Carbonatable CSC gains strength by reacting with carbon dioxide (CO2). While the concept of carbonation is well known, more information on the curing process is needed. This study focuses on studying the impact of drying time, carbonation duration, and degree of saturation (DOS) on the carbonation reaction of CSC mortar. Samples were exposed to different drying durations at controlled environmental conditions to reach various DOSs ranging from 100 to 0%. The samples were then exposed to carbonation under the same environmental conditions for different durations. Neutron radiography (NR) was performed on the samples during drying to determine the DOS corresponding to various drying durations. NR was also used during the carbonation period to determine the degree of carbonation (DOC) in real time. The impact of carbonation on the diffusivity of water vapor (Dh) and pore size distribution of CSC-based samples was examined using dynamic vapor sorption (DVS). It was concluded that the carbonation reaction increased as the DOS decreased from 100 to 40%. The carbonation reaction ceased for samples with DOS values less than 6% DOS. It was also concluded that as the DOC increased, the pore structure was refined, which led to a decrease in the Dh of the CSC mortar samples.

DOI:

10.14359/51739146


Document: 

22-217

Date: 

November 14, 2023

Author(s):

Amin K. Akhnoukh, Mathew Campbell

Publication:

Materials Journal

Abstract:

The U.S. National Oceanographic Services estimates 154,080 km (95,741 miles) of shorelines in the United States, where 163 miles/year are hardened by bulkheads and riprap. These shoreline protection techniques are costly and require frequent maintenance. Different agencies are examining “nature-based” solutions that combine vegetation with traditional concrete. Digital construction, advanced manufacturing, and innovative cementitious composites have additionally been proposed as potential means to lower material usage, cost, and environmental impact. This paper presents a novel advanced manufacturing technique using a reactive-diffusion morphological process, called “Dry FormingTM”, to 3-D print concrete structures of various shapes, sizes, and complexity with standard concrete mixes. This technology has reduced 60% of the material use; enhances local habitats, and increases the resiliency of the shoreline to sea level rise. The widespread of this technology would increase the resiliency in coastal communities, protect aquatic life, and protect waterfront public and private real estate investments.

DOI:

10.14359/51740264


Document: 

22-124

Date: 

September 1, 2023

Author(s):

Arindam Dey, Tara L. Cavalline, Miras Mamirov, and Jiong Hu

Publication:

Materials Journal

Volume:

120

Issue:

5

Abstract:

The use of recycled concrete aggregates (RCAs) in lieu of natural aggregates improves the sustainability of the built environment. Barriers to the use of RCA include its variable composition, including the residual mortar content (RMC), chemical composition, and its potential to contain contaminants, which can negatively affect the properties of concrete or present environmental concerns. In this study, a rapid, economical method to estimate the RMC and provide the chemical characterization of RCA was developed using a portable handheld X-ray fluorescence (PHXRF) device. Models were developed using reference tests (RMC test based on the thermal shock method and chemical composition from whole-rock analysis) to correlate PHXRF results to measured values. The PHXRF shows strong potential for estimating the RMC and chemical composition of RCA. Paired with locally calibrated reference samples, the test method could be used in laboratory or field applications to characterize RCA and increase its use in bound and unbound applications.

DOI:

10.14359/51738890


Document: 

21-483

Date: 

September 1, 2023

Author(s):

Nima Mohammadian Tabrizi, Davood Mostofinejad, and Mohammad Reza Eftekhar

Publication:

Materials Journal

Volume:

120

Issue:

5

Abstract:

This paper is aimed at investigating the effects of different fiber inclusion on the mechanical properties of ultra-high-performance concrete (UHPC) by adding mineral admixtures as cement replacement materials to reduce production costs and CO2 emissions of UHPC. Throughout this research, 21 mixture designs containing four cement substitution materials (silica fume, slag cement, limestone powder, and quartz powder) and three fibers (steel, synthetic macrofibers, and polypropylene) under wet and combined (autoclave, oven, and water) curing were developed. To investigate the mechanical properties in this research, a total of 336 specimens were cast to evaluate compressive strength, the modulus of rupture (MOR), and the toughness index. The findings revealed that at the combined curing, regarded as a new procedure, all levels of cement replacement recorded a compressive strength higher than 150 MPa (21.76 ksi). Furthermore, the mechanical properties of the mixture design containing microsilica and slag (up to 15%) were found to be higher than other cement substitutes. Also, it was shown that all levels of the fiber presented the MOR significantly close together, and samples made of synthetic macrofibers and steel fibers exhibited deflection-hardening behavior after cracking. The mixture design containing microsilica, slag, limestone powder, and quartzpowder, despite the significant replacement of cement (approximately 50%) by substitution materials, experienced a slight drop in strength. Therefore, the development of this mixture is optimal both economically and environmentally.

DOI:

10.14359/51738888


12345...>>

Results Per Page