NEUTRON RADIOGRAPHY MEASUREMENT OF SALT SOLUTION ABSORPTION IN MORTAR.

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.

[1]  Peng Zhang,et al.  Neutron radiography, a powerful method to determine time-dependent moisture distributions in concrete , 2011 .

[2]  W. Jason Weiss,et al.  Acoustic Emission and Low-Temperature Calorimetry Study of Freeze and Thaw Behavior in Cementitious Materials Exposed to Sodium Chloride Salt , 2014 .

[3]  D. Bentz,et al.  The Influence of Calcium Chloride Deicing Salt on Phase Changes and Damage Development in Cementitious Materials. , 2015, Cement & concrete composites.

[4]  Nicos Martys,et al.  Capillary transport in mortars and concrete , 1997 .

[5]  J. Weiss,et al.  Water Absorption and Critical Degree of Saturation Relating to Freeze-Thaw Damage in Concrete Pavement Joints , 2012 .

[6]  Göran Fagerlund,et al.  The international cooperative test of the critical degree of saturation method of assessing the freeze/thaw resistance of concrete , 1977 .

[7]  Anders Kaestner,et al.  Release of internal curing water from lightweight aggregates in cement paste investigated by neutron and X-ray tomography , 2011 .

[8]  D. Jacobson,et al.  Accurate measurement of the through-plane water content of proton-exchange membranes using neutron radiography. , 2012, Journal of applied physics.

[9]  Using X-Ray Absorption to Assess Moisture Movement in Cement-Based Materials , 2009 .

[10]  R. Hassanein.  Correction methods for the quantitative evaluation of thermal neutron tomography , 2006 .

[11]  W. Jason Weiss,et al.  An Overview of Joint Deterioration in Concrete Pavement: Mechanisms, Solution Properties, and Sealers , 2013 .

[12]  T. L. Brownyard,et al.  Studies of the Physical Properties of Hardened Portland Cement Paste , 1946 .

[13]  Lawrence L. Sutter,et al.  Observations of chloride ingress and calcium oxychloride formation in laboratory concrete and mortar at 5 °C , 2013 .

[14]  Elsabe P. Kearsley,et al.  Testing the durability of concrete with neutron radiography , 2005 .

[15]  R. D. Hooton,et al.  Effects of cyclic chloride exposure on penetration of concrete cover , 1999 .

[16]  J. Hanson,et al.  Hydrothermal transformation of the calcium aluminum oxide hydrates CaAl2O4·10H2O and Ca2Al2O5·8H2O to Ca3Al2(OH)12 investigated by in situ synchrotron X-ray powder diffraction , 2005 .

[17]  W. Jason Weiss,et al.  Using Neutron Radiography to Quantify Water Transport and the Degree of Saturation in Entrained Air Cement Based Mortar , 2015 .

[18]  Dwayne Harris,et al.  Using Ground-Penetrating Radar to Detect Indicators of Premature Joint Deterioration in Concrete Pavements , 2015 .

[19]  Bernard Y. Tao,et al.  Can Soy Methyl Esters Reduce Fluid Transport and Improve Durability of Concrete? , 2009 .

[20]  J. Weiss,et al.  Numerical and Experimental Assessment of Unsaturated Fluid Transport in Saw-Cut (Notched) Concrete Elements , 2009, SP-266: Modeling As a Solution to Concrete Problems CD.

[21]  D. Bentz,et al.  Effect of sample conditioning on the water absorption of concrete , 2011 .

[22]  S. Kelham,et al.  A WATER ABSORPTION TEST FOR CONCRETE , 1988 .

[23]  Daming Luo,et al.  Using Fick's Second Law and Nernst–Planck Approach in Prediction of Chloride Ingress in Concrete Materials , 2014 .

[24]  W. Jason Weiss,et al.  Conventional Portland Cement and Carbonated Calcium Silicate–Based Cement Systems , 2015 .

[25]  Mohammad Pour-Ghaz,et al.  Wetting and drying of concrete using aqueous solutions containing deicing salts , 2011 .

[26]  Yaghoob Farnam,et al.  The Influence of Calcium Chloride Salt Solution on the Transport Properties of Cementitious Materials , 2015 .

[27]  L. Hanžič,et al.  Relationship between liquid sorptivity and capillarity in concrete , 2003 .

[28]  W. Jason Weiss,et al.  The Influence of Pore Solutions Properties on Drying in Cementitious Materials , 2014 .

[29]  Manuel R. Conde,et al.  Properties of aqueous solutions of lithium and calcium chlorides: formulations for use in air conditioning equipment design , 2004 .

[30]  Rainer Schulin,et al.  Quantitative Imaging of Infiltration, Root Growth, and Root Water Uptake via Neutron Radiography , 2008 .

[31]  Stuart Lyon,et al.  Mechanism of Friedel's salt formation in cements rich in tri-calcium aluminate , 1996 .