Development of Performance Properties of Ternary Mixtures: Field Demonstrations and Project Summary

Supplementary cementitious materials (SCM) have become common parts of modern concrete practice. The blending of two or three cementitious materials to optimize durability, strength, or economics provides owners, engineers, materials suppliers, and contractors with substantial advantages over mixtures containing only portland cement. However, these advances in concrete technology and engineering have not always been adequately captured in specifications for concrete. Users need specific guidance to assist them in defining the performance requirements for a concrete application and the selection of optimal proportions of the cementitious materials needed to produce the required durable concrete. The fact that blended cements are currently available in many regions increases options for mixtures and thus can complicate the selection process. Both Portland and blended cements have already been optimized by the manufacturer to provide specific properties (such as setting time, shrinkage, and strength gain). The addition of SCMs (as binary, ternary, or even more complex mixtures) can alter these properties, and therefore has the potential to impact the overall performance and applications of concrete. This report is the final of a series of publications describing a project aimed at addressing effective use of ternary systems. The work was conducted in several stages and individual reports have been published at the end of each stage

Excess foundry sand characterization and experimental investigation in controlled low-strength material and hot-mixing asphalt

This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: a statistically sound evaluation of the characterization of foundry sand, a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at Nini, Ndes, and Nmax. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies.Structural Engineerin

Geotechnical and leaching properties of flowable fill incorporating waste foundry sand

Abstract not availableAn Deng and Paul J. Tikalsk

Influence of portland cement characteristics on alkali silica reactivity

The findings of this study which evaluated 21 portland cements identified K2O and Na2Oeq as significantly contributing to ASR expansion with a less strong correlation to SO3 content The conclusions are based on results of ASTM C 441 Tests. Response surface modeling has identified a negative trend of clinker SiO2 and a direct trend of Na2Oeq as significantly contributing to ASR expansion. The ASTM C 227 analytical results were less conclusive and proved to be a poor indicator of the effects of cement variables in the expansion in tests up to 1 year in duration. In contrast, ASTM C 441 rapidly and clearly delineated the cements contribution to ASR expansion.Structural Engineerin

Statistical variations in chloride diffusion in concrete bridges

Designing structures for longer life requires that a reliable means be developed to predict the mechanisms related to durability. The paper introduces the simulation-based reliability assessment (SBRA) method for the probabilistic prediction of chloride diffusion. Data are presented from the in-place measurement of chloride penetration and concrete cover from more than 200 samples taken from 40 bridge decks in the northeastern U.S. The bridge decks were constructed under identical construction and design specifications over a 13-year period and exposed to deicing salts as well as normal environmental cycles. The paper illustrates the effect of variations in diffusion coefficients and cover depths using histograms. The research used Monte Carlo simulation to evaluate Fick’s second law using an expansion solution to Crank’s error function. The result shows that the initiation of corrosion from the diffusion of chlorides can be delayed for decades by using high-performance concrete with lower diffusion coefficients

Probabilistic time-dependent sensitivity analysis of HPC bridge deck exposed to chlorides

A robust finite element based reinforced concrete bridge deck corrosion initiation model is applied for time dependent probabilistic sensitivity analysis. The model is focused on uncertainties in the governing parameters that include variation of high performance concrete (HPC) diffusion coefficients, concrete cover depth, surface chloride concentration, holidays in reinforcements, coatings and critical chloride threshold level in several steel reinforcements. The corrosion initiation risk is expressed in the form of probability over intended life span of the bridge deck. Conducted study shows the time dependent sensitivity analysis to evaluate the significance of governing parameters on chloride ingress rate, various steel reinforcement protection and the corrosion initiation likelihood. Results from this probabilistic analysis provide better insight into the effect of input parameters variation on the estimate of the corrosion initiation risk for the design of concrete structures in harsh chloride environments.Web of Science19331330

Influence of Portland Cement Characteristics on Alkali Silica Reactivity

The findings of this study which evaluated 21 portland cements identified K2O and Na2Oeq as significantly contributing to ASR expansion with a less strong correlation to SO3 content The conclusions are based on results of ASTM C 441 Tests. Response surface modeling has identified a negative trend of clinker SiO2 and a direct trend of Na2Oeq as significantly contributing to ASR expansion. The ASTM C 227 analytical results were less conclusive and proved to be a poor indicator of the effects of cement variables in the expansion in tests up to 1 year in duration. In contrast, ASTM C 441 rapidly and clearly delineated the cements contribution to ASR expansion. TRB 2003 Annual Meeting CD-ROM Original paper submittal – not revised by author

Excess Foundry Sand Characterization and Experimental Investigation in Controlled Low-Strength Material and Hot-Mixing Asphalt

This report provides technical data regarding the reuse of excess foundry sand. The report addresses three topics: a statistically sound evaluation of the characterization of foundry sand, a laboratory investigation to qualify excess foundry sand as a major component in controlled low-strength material (CLSM), and the identification of the best methods for using foundry sand as a replacement for natural aggregates for construction purposes, specifically in asphalt paving materials. The survival analysis statistical technique was used to characterize foundry sand over a full spectrum of general chemical parameters, metallic elements, and organic compounds regarding bulk analysis and leachate characterization. Not limited to characterization and environmental impact, foundry sand was evaluated by factor analyses, which contributes to proper selection of factor and maximization of the reuse marketplace for foundry sand. Regarding the integration of foundry sand into CLSM, excavatable CLSM and structural CLSM containing different types of excess foundry sands were investigated through laboratory experiments. Foundry sand was approved to constitute a major component in CLSM. Regarding the integration of foundry sand into asphalt paving materials, the optimum asphalt content was determined for each mixture, as well as the bulk density, maximum density, asphalt absorption, and air voids at Nini, Ndes, and Nmax. It was found that foundry sands can be used as an aggregate in hot-mix asphalt production, but each sand should be evaluated individually. Foundry sands tend to lower the strength of mixtures and also may make them more susceptible to moisture damage. Finally, traditional anti-stripping additives may decrease the moisture sensitivity of a mixture containing foundry sand, but not to the level allowed by most highway agencies

BIBSnet

<p>This software provides the utility of creating a nnU-Net anatomical MRI segmentation and mask with a infant brain trained model for the purposes of circumventing JLF within Nibabies.</p&gt

BIBSnet

<p>This software provides the utility of creating a nnU-Net anatomical MRI segmentation and mask with a infant brain trained model for the purposes of circumventing JLF within Nibabies.</p&gt