Using Neutron Radiography to Quantify Water Transport and the Degree of Saturation in Entrained Air Cement Based Mortar

Lucero, Catherine; Bentz, Dale P.; Hussey, Daniel S.; Jacobson, David L.; Weiss, Jason

doi:10.1016/j.phpro.2015.07.077

Cited by 38 publications

(23 citation statements)

References 12 publications

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“…Figure 7a and 7b exhibit moisture profiles with a steep gradient at the wetting front that maintain a constant shape as time increases, as expected [18], [32]. However, in Figure 7c and 7d, there is a clear increase in the change in degree of saturation at the far end of the sample after the water front reaches that edge, as indicated by the local peak in the 10 h data at a distance of about 48 mm.…”

Section: Resultssupporting

confidence: 68%

“…These effects can make quantifying water difficult. However, with total water thicknesses less than about 5 mm [0.20 in], the relationship between optical density and water thickness remains approximately linear [26], [32]. The optical density is defined as…”

Section: Experimental Investigationmentioning

confidence: 99%

“…The optical density can be normalized by the sample thickness to define the composite attenuation coefficient of the mortar ( μ mortar ) [32]. By normalizing to the thickness of the sample ( t sample ), the optical densities from multiple mortar samples can be compared to each other.…”

Section: Experimental Investigationmentioning

confidence: 99%

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Neutron Radiography Measurement of Salt Solution Absorption in Mortar

Lucero¹,

Spragg²,

Bentz³

et al. 2017

ACI Materials Journal

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Some concrete pavements in the US have recently exhibited premature joint deterioration. It is hypothesized that one component of this damage can be attributed to a reaction that occurs when salt-laden water is absorbed in the concrete and reacts with the matrix. This study examines the absorption of CaCl2 solution in mortar via neutron imaging. Mortar specimens were prepared with water to cement ratios, (w/c), of 0.36, 0.42 and 0.50 by mass and exposed to chloride solutions with concentrations ranging from 0 % to 29.8 % by mass. Depth of fluid penetration and moisture content along the specimen length were determined for 96 h after exposure. At high salt concentration (29.8 %), the sorption rate decreased by over 80 % in all samples. Along with changes in surface tension and viscosity, CaCl2 reacts with the cement paste to produce products (Friedel’s salt, Kuzel’s salt, or calcium oxychloride) that block pores and reduce absorption.

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Section: Resultssupporting

confidence: 68%

Section: Experimental Investigationmentioning

confidence: 99%

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Neutron Radiography Measurement of Salt Solution Absorption in Mortar

Lucero¹,

Spragg²,

Bentz³

et al. 2017

ACI Materials Journal

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“…Lucero, Bentz, Hussey, Jacobson, and Weiss (2015) used neutron radiography to examine the relationship between the initial rate of absorption and pores that were being filled. Lucero et al (2015) proposed that the initial absorption (shown in blue) corresponds to the filling of gel and capillary pores while the secondary rate of sorption (shown in red) was related to the filling of larger pores like air voids. The impacts of the sorption-based model on concrete specifications have been discussed by Todak et al (2015).…”

Section: Summary Of Degree Of Saturationmentioning

confidence: 99%

“…The findings from Lucero et al (2015) have indicated that the transition between the initial absorption and secondary absorption (commonly referred to as the nick point) can be described by the degree of saturation that fills in all the pores in a concrete with the exception of the air voids (this would include the gel and capillary pores). The Powers-Brownyard (1948) model can be used to determine the degree of saturation at the nick point.…”

Section: Summary Of Degree Of Saturationmentioning

confidence: 99%

Synthesis: Accelerating Implementation of Research Findings to Reduce Potential Concrete Pavement Joint Deterioration

Weiss¹,

Olek²,

Whiting³

et al. 2019

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JOINT TRANSPORTATION RESEARCH PROGRAMThe Joint Transportation Research Program serves as a vehicle for INDOT collaboration with higher education institutions and industry in Indiana to facilitate innovation that results in continuous improvement in the planning, design, construction, operation, management and economic efficiency of the Indiana transportation infrastructure. AbstractDistress has recently been observed in the joints of some concrete pavements, primarily in the wet-freeze states. This distress often begins in longitudinal joints, followed by transverse joints and results in the significant loss of material from the joint area. Although it may only affect approximately 10% of the concrete pavements system-wide, it greatly reduces the service life and increases maintenance costs of the pavements it effects. Primary issues that emerged from studies on this phenomenon include the importance of the timing of joint sawing, the width of the joint opening, degree of concrete or joint sealing, drainage and degree of saturation of the concrete at the joint, quality of the air void system, role of deicing chemicals, quality of curing, and the degree of restraint at the joint. Although this broad collection of issues implies that we still lack complete understanding of all causes of joint deterioration, it also makes it pretty clear that the observed damage is a result of combination of several factors. This study synthesizes completed research related to concrete pavements joint deterioration and provides information to advance the knowledge and understanding of the variables involved in in this deterioration process and suggests the best practices that can lead to its reduction or mitigation. 17.

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Impact of bacterial admixtures on the compressive and tensile strengths, permeability, and pore structure of ternary mortars: Comparative study of ureolytic and phototrophic bacteria

Aceituno‐Caicedo,

Shvarzman,

Zhutovsky

et al. 2023

Biotechnology Journal

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The addition of bacterial biomass to cementitious materials can improve strength and permeability properties by altering the pore structure. Photoautotrophic bacteria are understudied mortar bio‐additives that do not produce unwanted by‐products compared to commonly studied ureolytic species. This study directly compares the impact of the addition of heterotrophic Bacillus subtilis to photoautotrophic Synechocystis sp. PCC6803 on mortar properties and microstructure. Cellulose fibers were used as a bacteria carrier. A commercial concrete healing agent composed of dormant bacterial spores was also tested. Strength, water absorption tests, mercury intrusion porosimetry, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy were applied to experimental mortar properties. The photoautotrophic modifications had a stronger positive impact on mortar strength and permeability properties than sporulated heterotrophic modifications due to differences in surface properties and production of exopolysaccharides. The findings provide support for photoautotrophic species as additives for mortars to move away from ammonia‐generating species.

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Using Neutron Radiography to Quantify Water Transport and the Degree of Saturation in Entrained Air Cement Based Mortar

Cited by 38 publications

References 12 publications

Neutron Radiography Measurement of Salt Solution Absorption in Mortar

Neutron Radiography Measurement of Salt Solution Absorption in Mortar

Synthesis: Accelerating Implementation of Research Findings to Reduce Potential Concrete Pavement Joint Deterioration

Impact of bacterial admixtures on the compressive and tensile strengths, permeability, and pore structure of ternary mortars: Comparative study of ureolytic and phototrophic bacteria

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