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Spall Strength Measurements of Concrete for Varying Aggregate Sizes

Description: Controlled impact experiments have been performed to determine the spall strength of four different concrete compositions. The four concrete compositions are identified as, `SAC-5, CSPC', ("3/4") large, and ("3/8") small, Aggregate. They differ primarily in aggregate size but with average densities varying by less than five percent. Wave profiles from sixteen experiments, with shock amplitudes of 0.07 to 0.55 GPa, concentrate primarily within the elastic regime. Free-surface particle velocity measurements indicate consistent pullback signals in the release profiles, denoting average span strength of approximately 40 MPa. It is the purpose of this paper to present spall measurements under uniaxial strain loading. Notwithstanding considerable wave structure that is a unique characteristic to the heterogeneous nature of the scaled concrete, the spall amplitudes appear reproducible and consistent over the pressure range reported in this study.
Date: May 5, 1999
Creator: Chhabildas, Lalit C.; Kipp, Marlin E.; Reinhart, William D. & Wilson, Leonard T.
Partner: UNT Libraries Government Documents Department

Geochemical Methods for the Identification of ASR Gel

Description: This paper presents a geochemical method for staining various products of the alkali-silica reaction. The method is based on both the composition of ASR gel and one of its properties (the ability to exchange cations with a fluid). The stained concrete can be observed in normal light and serves as both a rapid field screening method and a useful aid for detailed petrographic examinations.
Date: July 1, 1998
Creator: Guthrie, G.D. & Carey, J.W.
Partner: UNT Libraries Government Documents Department

Analysis of Potential Concerete Floor Decontamination Technologies

Description: During the decontamination and decommissioning (D&D) activities to be conducted at the Femald Environmental Management Project (FEMP), contaminated concrete waste will be generated from the D&D of approximately 200 buildings and other structures [1]. The U.S. Department of Energy (DOE) owns the Fernald site. The site is a contractor-operated federal facility that produced high-purity uranium metal products for the DOE and its predecessor agency, the Atomic Energy Commission, from 1952 to 1989. Thorium being ores were also processed at FEMP, but on a smaller scale. Production activities ceased in 1989, and the production mission of the facility ended formally in 1991. FEMP was included on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List in 1989. The current mission of the site is environmental restoration according to the requirements specified by CERCLA [1]. Decontamination and decommissioning activities require the treatment of concrete floors to segregate technetium-99 contaminated concrete from the remainder of the concrete. Many proven commercial stiace removal technologies are available. These processes vary in aggressiveness, stiety requirements, waste generation, capital requirements, and operating and maintenance costs.
Date: August 6, 1997
Creator: Ebadian, M. A.
Partner: UNT Libraries Government Documents Department

Design Review Report for Concrete Cover Block Replaced by Steel Plate

Description: The design for the steel cover plates to replace concrete cover blocks for U-109 was reviewed and approved in a design review meeting. The design for steel plates to replace concrete blocks were reviewed and approved by comparison and similarity with U-109 for the following additional pits: 241-U-105. 241-I-103, 241-Ax-101. 241-A-101, 241-SX-105, 241-S-A, 241-S-C, 241-SX-A.
Date: July 27, 2000
Creator: JAKA, O.M.
Partner: UNT Libraries Government Documents Department

Developing improved relationships between microstructure and creep and shrinkage of cement-based materials. Final report for the period September 9, 1998 - July 31, 2000

Description: The shrinkage of concrete that occurs on drying is a complex function of age of concrete, rate of drying, temperature, and composition of concrete. This project investigated the fundamental relationships between microstructure and shrinkage. In order to accomplish this goal a new quantitative image analysis technique was developed to analyze the distribution of strain throughout the microstructure during drying. The technique has been verified at NIST and the results have provided new insights. A major result of this effort has been the redefinition of microstructure of cement paste. Large deformations, both expansive and compressive, occur throughout the microstructure. These large deformations can be best explained by considering the calcium silicate phase to be a colloid. A new model for calcium silicate hydrate was developed.
Date: January 1, 2001
Creator: Jennings, Hamlin M.
Partner: UNT Libraries Government Documents Department

UCom: Ultra-wideband Communications in Harsh Propagation Environments

Description: LLNL has developed an ultra-wideband (UWB) system that provides unique, through-the-wall wireless communications in heavy metallic and heavy concrete indoor channels. LLNL's UWB system is the only available wireless communications system that performs successfully and reliably in facilities where conventional narrowband communications usually fail due to destructive reflections from multiple surfaces. These environments include: cargo ships and reinforced, heavy concrete buildings. LLNL's revolutionary system has applications for the military, as well as commercial indoor communications in multistory buildings, and cluttered industrial structures.
Date: March 14, 2007
Creator: Nekoogar, F
Partner: UNT Libraries Government Documents Department

PERIODIC RADIATION SURVEY. CORE I, SEED 1. Section 3. Test Results T- 612394

Description: Radiation levels inside the concrete enclosures but outside the reactor plant containers after shutdown were determined. Radiation levels in the 1AC, 1BC boiler chamber enclosures and in the reactor chamber enclosure were on the average higher than in previous tests. The highest reading obtained was 7.5 mr/ hr and the lowest reading was 0.03 mr/hr; the mean level was 3.76 mr/hr as compared to 1.37 mr/hr in previous tests. (W.L.H.)
Date: June 17, 1960
Partner: UNT Libraries Government Documents Department

RADIATION LEVELS IN THE VICINITY OF THE PURIFICATION DEMINERALIZERS. CORE 1, SEED 1. Test Results T-641306

Description: BS>A test was performed to determine the activity build-up inside the 1AC and 1BD purification demineralizer concrete enclosure. A maximum radiation level of 1100 mr/hr was detected inside the 1AC demineralizer enclosure at a point 10.0 ft from the top. The maximum radiation level inside the 1BD enclosure was 700 mr/hr at a point 9.5 ft below the top. An analysis of data from five tests indicates that the extent of the activity build-up, as well as the level of activity, is definitely increasing. (W.L.H.)
Date: October 10, 1960
Partner: UNT Libraries Government Documents Department

Hydrothermal alteration of cementitious materials, Part II: second and third batch of samples

Description: This report describes experiments designed to provide data for a quick engineering assessment of the microstructural, mineralogical, and mechanical changes in hydrothermally altered concrete and changes in associated water chemistry.
Date: October 25, 1997
Creator: Meike, A. & Myers, K. B. L.
Partner: UNT Libraries Government Documents Department

Elastic shock response and spall strength of concrete

Description: Impact experiments have been performed to obtain shock compression, release response, and spall strength of two scaled concrete formulations. Wave profiles from a suite of ten experiments, with shock amplitudes of 0.08 to 0.55 GPa, focus primarily on the elastic regime. Despite considerable wave structure that develops at the shock transits these heterogeneous targets, consistent pullback signals were identified in the release profiles, indicating a spall strength of about 30 MPa. Explicit modeling of the concrete aggregate structure in numerical simulations provides insight into the particle velocity records.
Date: August 1, 1997
Creator: Kipp, M.E.; Chhabildas, L.C. & Reinhart, W.D.
Partner: UNT Libraries Government Documents Department

Electrokinetic decontamination of concrete. Final report, August 3, 1993--September 15, 1996

Description: The ELECTROSORB{reg_sign} {open_quotes}C{close_quotes} process is an electrokinetic process for decontaminating concrete. ELECTROSORB{reg_sign} {open_quotes}C{close_quotes} uses a carpet-like extraction pad which is placed on the contaminated concrete surface. An electrolyte solution is circulated from a supporting module. This module keeps the electrolyte solution clean. The work is advancing through the engineering development stage with steady progress toward a full scale demonstration unit which will be ready for incorporation in the DOE Large Scale Demonstration Program by Summer 1997. A demonstration was carried out at the Mound Facility in Miamisburg, Ohio, in June 1996. Third party verification by EG&G verified the effectiveness of the process. Results of this work and the development work that proceeded are described herein.
Date: December 31, 1998
Partner: UNT Libraries Government Documents Department

NEW NONLINEAR ACOUSTIC TECHNIQUES FOR NDE

Description: Acoustic nonlinearity in a medium may occur as a result of a variety of mechanisms. Some of the more common nonlinear effects may come from: (1) one or several cracks, volumetrically distributed due to age or fatigue or single disbonds or delamination; (2) imperfect grain-to-grain contacts, e.g., materials like concretes that are cemented together and have less than perfect bonds; (3) hard parts in a soft matrix, e.g., extreme duty materials like tungsten/copper alloys; or (4) atomic-scale nonlinearities. Nonlinear effects that arise from the first two mechanisms are considerably larger than the last two; thus, we have focused considerable attention on these. The most pervasive nonlinear measure of damage today is a second harmonic measurement. We show that for many cases of interest to NDE, a second harmonic measurement may not be the best choice. We examine the manifestations of nonlinearity in (nonlinear) materials with cracks and/or imperfect bonds and illustrate their applicability to NDE. For example, nonlinear resonance frequency shifts measured at increasing drive levels correlate strongly with the amount of ASR (alkali-silica reaction) damage of concrete cores. Memory effects (slow dynamics) also seem to correlate with the amount of damage.
Date: September 1, 2000
Creator: TENCATE, J. A.
Partner: UNT Libraries Government Documents Department

Phase 3 Final Topical Report for the Remote Operated Vehicle with C02 Blasting (ROVCO2)

Description: This report documents the third and final phase of the Remote Operated Vehicle with CO2 Blasting (ROVCO2) Program. The Program=s goal is to develop and demonstrate a tool to improve the productivity of concrete floor decontamination. In Phase 3 of the ROVCO2 program, the workhead and the COYOTEE end-effector were redesigned, and effectiveness and productivity tests were performed. This report documents the development activities. The results show that the ROVCO2 system is an efficient decontamination tool, but with relatively slow production rates.
Date: April 14, 1998
Partner: UNT Libraries Government Documents Department

The structural failure probability analysis of pipe impact onto a concrete wall.

Description: The purpose of this study was to perform a probabilistic safety assessment of a steel pipe impacting against a concrete wall. The probabilistic structural integrity evaluation was coupled with a deterministic FE program, NEPTUNE. This evaluation included deterministic modeling, definition of random variables, description of failure criterion or limit state function, running the probabilistic analysis and reviewing the final results.
Date: May 15, 2002
Creator: Kulak, R.; Merchertas, P. & Petkevicius, K.
Partner: UNT Libraries Government Documents Department

Evaluation of Simplified Methods for Estimating Shear Capacity Using JNES/NUPEC Low-Rise Concrete Shear Wall Cyclic Test Data.

Description: The simplified methods in current codes for determining the shear capacity of reinforced concrete shear walls had mostly been validated using the test results of single-element shear walls. Recently available JNES/NUPEC test data of reinforced concrete shear walls under multi-directional cyclic loadings provided a unique opportunity to investigate the adequacy of the simplified methods for use in situations with strong interaction effects. A total of 11 test specimens with aspect ratios between 0.47 and 0.87 have been used in the assessment. Two simplified methods from the ACI 349-01 standard [1] and one from the ASCE 43-05 standard [2] have been evaluated. This paper also presents the development of an adjustment factor to consider the aspect ratio and the development of two approaches to consider interaction effects for one of the simplified methods. It concludes with the insights on the applicability of the code methods when interaction effects exist.
Date: June 1, 2008
Creator: Nie,J.; Braverman, J.; Hofmayer, C. & Ali, S.
Partner: UNT Libraries Government Documents Department

Heat Exchanger Support Bracket Design Calculations

Description: This engineering note documents the design of the heat exchanger support brackets. The heat exchanger is roughly 40 feet long, 22 inches in diameter and weighs 6750 pounds. It will be mounted on two identical support brackets that are anchored to a concrete wall. The design calculations were done for one bracket supporting the full weight of the heat exchanger, rounded up to 6800 pounds. The design follows the American Institute of Steel Construction (AISC) Manual of steel construction, Eighth edition. All calculated stresses and loads on welds were below allowables.
Date: January 12, 1995
Creator: Rucinski, Russ
Partner: UNT Libraries Government Documents Department