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International Concrete Abstracts Portal

Showing 1-5 of 2833 Abstracts search results

Document: 

22-399

Date: 

April 1, 2024

Author(s):

Harshita Garg, Kai Yang, Anthony G. Cohn, Duncan Borman, Sreejith V. Nanukuttan, P.A. Muhammed Basheer

Publication:

Materials Journal

Volume:

121

Issue:

2

Abstract:

The recent increased interest in structural health monitoring (SHM) related to material performance has necessitated the application of advanced data analysis techniques for interpreting the realtime data in decision-making. Currently, an accurate and efficient approach for the timely analyses of large volumes of uncertain sensor data is not well-established. This paper proposes an automated clustering-based piecewise linear regression (ACPLR)-SHM methodology for handling, smoothing, and processing large data sets. It comprises two main stages, where the gaussian weighted moving average (GWMA) filter is used to smooth noisy data obtained from electrical resistance sensors, and piecewise linear regression (PLR) predicts material properties for assessing the performance of concrete in service. The obtained values of stabilized resistance and derived values of diffusion coefficients using this methodology have clearly demonstrated the benefit of applying ACPLR to the sensor data, thereby classifying the performance of different types of concrete in service environments.

DOI:

10.14359/51740370


Document: 

21-335

Date: 

April 1, 2024

Author(s):

Zainab Hashim Abbas Alsalami and Fatima Hashim Abbas

Publication:

Materials Journal

Volume:

121

Issue:

2

Abstract:

Ultra-high-performance concrete (UHPC) is considered a sophisticated concrete construction solution for infrastructure and other structures because of its premium mechanical traits and superior durability. Fibers have a special effect on the properties of UHPC, especially as this type of concrete suffers from high autogenous shrinkage due to its high cementitious content, so the properties and volume fraction of fibers are more important in UHPC. This study will describe previous related works on the mechanical behavior of UHPC specimens reinforced with micro- and nanoscale fibers, and compare of the behavior of UHPC reinforced with microfibers to that reinforced with nanofibers. The compressive strength, flexural behavior, and durability aspects of UHPC reinforced with nanoand/or microscale variable types of fibers were studied to highlight the issues and make a new direction for other authors.

DOI:

10.14359/51740369


Document: 

22-424

Date: 

April 1, 2024

Author(s):

C. Pleesudjai, D. Patel, K. A. Williams Gaona, M. Bakhshi, V. Nasri, and B. Mobasher

Publication:

Materials Journal

Volume:

121

Issue:

2

Abstract:

Statistical process control (SPC) procedures are proposed to improve the production efficiency of precast concrete tunnel segments. Quality control test results of more than 1000 ASTM C1609/C1609M beam specimens were analyzed. These specimens were collected over 18 months from the fiber-reinforced concrete (FRC) used for the production of precast tunnel segments of a major wastewater tunnel project in the Northeast United States. The Anderson-Darling (AD) test for the overall distribution indicated that the data are best described by a normal distribution. The initial residual strength parameter for the FRC mixture, f D 600, is the most representative parameter of the post-crack region. The lower 95% confidence interval (CI) values for 28-day flexural strength parameters of f1, f D 600, and f D 300 exceeded the design strengths and hence validated the strength acceptability criteria set at 3.7 MPa (540 psi). A combination of run chart, exponentially weighted moving average (EWMA), and cumulative sum (CUSUM) control charts successfully identified the out-of-control mean values of flexural strengths. These methods identify the periods corresponding to incapable manufacturing processes that should be investigated to move the processes back into control. This approach successfully identified the capable or incapable processes. The study also included the Bootstrap Method to analyze standard error in the test data and its reliability to determine the sample size.

DOI:

10.14359/51740373


Document: 

23-152

Date: 

April 1, 2024

Author(s):

Ronald Lichtenwalner and Joseph T. Taylor

Publication:

Materials Journal

Volume:

121

Issue:

2

Abstract:

This experimental study evaluated the correlation between measured concrete expansion from a modified version of the miniature concrete prism test (MCPT) with the concentration of chemical markers leached from the prisms into an alkaline soak solution. Fifteen concrete mixture designs were tested for expansion and soak solution concentrations over time. The changes in expansion and soak solution concentrations were found to correlate well even with variations in alkali loading and substitution of cement with Class F fly ash. A model was developed to estimate the expansion potential of concrete based on an expansion reactivity index (ERI) that incorporated the concentrations of silicon, sulfate, calcium, and aluminum. The relationship between ERI and expansion was then used to identify potentially expansive concrete mixtures using the ERI of cores taken from a structure exhibiting potential alkalisilica reaction (ASR) expansion and concrete cylinders matching the mixture designs of the MCPT specimens.

DOI:

10.14359/51740374


Document: 

22-288

Date: 

April 1, 2024

Author(s):

Christian Negron-McFarlane, Eric Kreiger, Lynette Barna, Peter Stynoski, and Megan Kreiger

Publication:

Materials Journal

Volume:

121

Issue:

2

Abstract:

An experimental investigation was carried out using the volumetric proportioning approach to achieve printable portland cement concrete mixtures. The types of aggregates investigated were rounded pea gravel and coarse and fine sand. The test matrix of potential concrete mixtures was prepared based on watercement ratios (w/c) of 0.46 to 0.48, sand-to-stone ratios (sa/st) of 1.18 to 1.91, and paste-aggregate ratios (p/a) of 0.74 to 0.81. The workability and early-age strength of fresh concrete were characterized by field-friendly flow-table and unconfined compressive strength (UCS) tests. Test results indicated that the w/c, sa/st, and p/a all significantly affect fresh concrete pumpability and early-age strength. The overall research results revealed that pumpability and buildability can be evaluated with these two tests. The results of these two tests together are used to define a printable region.

DOI:

10.14359/51740265


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