Yunping Xi - Colorado LTAP

LTAP Staff > Yunping Xi

Yunping Xi, Ph.D. - University Administrator

Professor Civil, Environmental, and Architectural Engineering University of Colorado at Boulder Boulder, CO 80303
Tel: (303) 492-8991, Fax: (303) 492-7317

email: yunping.xi@colorado.edu

Education

Ph.D. in Structural Engineering, Northwestern University, Evanston, IL. (1991).
M.S. in Structural Engineering, Central Research Institute of Building and Construction, Beijing (1985).
B.S. in Civil Engineering, Beijing Institute of Civil Engineering and Architecture (1982).

Employment History

2005 – Present Professor, University of Colorado at Boulder
2000 – 2005 Associate professor, University of Colorado at Boulder
1997 – 2000 Assistant professor, University of Colorado at Boulder
1993 – 1996 Assistant professor, Drexel University
1991 – 1993 Research scientist, Northwestern University
1987 – 1988 Visiting scholar, Northwestern University
1985 – 1987 Structural engineer, Beijing Central Research Inst. of Building and Construction.
1982 – 1983 Structural engineer, Beijing Design Institute of Building and Construction.

Awards and Recognitions

Research development award 2004. Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder.

Young Researcher’s award for academic year 1998-1999. Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder.

Faculty advisor for Drexel teams in American Concrete Institute (ACI) beam competition. In 1993, First prize for the highest ultimate load was awarded to the Drexel team. In 1994, First prize for the highest ultimate load was awarded to one of the Drexel teams. First prize for the best prediction was awarded to another Drexel team.

Research Activities

Research Interests and fundings

Theoretical analysis and experimental study on long term durability of reinforced concrete structures.
Monitoring and simulation of long-term performance of reinforced concrete and steel structures.
Evaluation of performance of materials and structures under high temperatures.
Development of sustainable construction materials (recycling of fly ash, waste glass, and waste tires).

Since 1993, Dr. Xi has participated more than 70 sponsored projects as PI or co-PI. The total funding is more than $6.2 million dollars. The following are partial lists of the research projects.

Ongoing Projects

Federal Highway Administration (FHWA) and Colorado DOT “Colorado Local Technical Assistance Program for the Roadway Infrastructure System”, 1998 – 2009, $2,138,631 (PI: Y. Xi).
NSF “An Integrated Power Aware Sensor-Simulation Network System for Long-Term Performance Assessment of Concrete Infrastructures”, 2008 – 2010, $600,000 (PI: Cai, X.C., co-PIs: Y. Xi and R. Zane).
NSF “Penetration of Multi-Components De-icing Salts in Non-Saturated Concrete Structures”, 2007 – 2009, $150,000 (PI: Y. Xi, and co-PI: L.Y. Li).
CDOT “Evaluation and Monitoring of Performance of Bridge Deck Sealers”, 2008-2009, $60,000 (PI: Y. Xi).
Oak Ridge National Laboratory (ORNL) “Thermal Response of Reinforced Concrete Structures”, 2008-2009, $90,000 (PI: K. Willam, and co-PI: Y. Xi).
Colorado Department of Public Health and Environment (CDPHE) “Premixed Rubberized Insulation Mortar (PRIM)”, 2008-2010, $133,929 (PI: Y. Xi).
Colorado Department of Transportation (CDOT) “Strategic Evaluation of Different Topical Protection Systems for Bridge Decks and the Associated Life-Cycle Cost Analysis”, 2007-2008, $30,000 (PI: Y. Xi).
Colorado Department of Transportation (CDOT) “Application of Roller Compacted Concrete (RCC) in Colorado’s Roadways”, 2009-2011, $20,000 (PI: Y. Xi).

Completed projects (partial list as PI or co-PI, listed chronologically)

New Jersay (NJ) DOT “Chloride Permeability of Concrete with Silica Fume and Other Admixtures”, 1996 – 1998, $37,835 (PI: Y. Xi).
Ben Franklin Technology Center “Use of Recycled Glass as Raw Material in the Manufacture of Portland Cement”, 1996 – 1998, $82,990 (PI: Y. Xi).
New York State Energy Research and Development Authority (NYSERDA) via. Columbia University “Use of Recycled Glass and Fly Ash for Precast Concrete Products”, 1995 – 1997, $25,214 (PI: Y. Xi).
Air Force “Dynamic Performance Evaluation of Conventional and Non-Conventional Concrete, 1997 – 1998, $75,000 (PI: K. Willam; co-PI: Y. Xi).
CDOT “Roadway Safety Training”, 1998 – 2008, $135,000 (PI: Y. Xi).
NSF “Accelerated Testing and Reliable Modeling of Concrete Durability under Coupled Environmental and Mechanical Loadings”, sponsored by National Science Foundation, 1998 – 2002, $342,000 (PI: Y. Xi; co-PIs: K. Willam and D.M. Frangopol).
NSF “Research Equipment Grant: Upgrade of the materials testing system”, 1998 – 1999, $84,625 (PI: Y. Xi; co-PIs: B. Shing and K. Willam).
Federal Aviation Administration (FAA) “Fiber Optic Sensor Monitoring and Earthquake Analysis of TRACON Facility at Denver International Airport”, 1998 – 2001, $74,817 (PI: S. Sture; co-PI: Y. Xi).
CDOT “Evaluation of CDOT current and Potential Steel Corrosion Protection Measures”, 2000 – 2002, $40,000 (PI: Y. Xi).
Lockheed Martin via. Colorado Advanced Materials Institute (CAMI): “Evaluation of High-Temperature-Capable Fabric Materials”, 2000-2001, $10,000 (PI: Y. Xi).
CTS Wireless “Frequency Shift of Piezoelectric Devices”, 2000 – 2002, $27,000 (PI: Y. Xi).
CDOT “Evaluation of Fiber Reinforced Polymer Reinforced Bridge Decks”, 2000 – 2001, $245,000 (PI: B. Shing; co-PIs: Y. Xi and D.M. Frangopol).
CDOT “Field Investigation of Cracking in Newly Constructed Bridge Decks”, 2000 – 2002, $30,000 (PI: Y. Xi).
NSF “NATO-NSF Workshop on Model-Based Simulation of Durability of Materials and Structures”, 2000 – 2002, $34,510 (PI: Y. Xi).
CDOT “Comparative Study on Corrosiveness of Different De-Icing Agents: Magnesium Chloride, Sodium Chloride, and Caliber M1000", 2001 – 2002, $71,033 (PI: Y. Xi).
NSF “A Live-Data Simulation System and Applications to Highway Bridge Performance Prediction”, 2001 – 2005, $451,343 (PI: X.C. Cai; co-PI: Y. Xi).
CDOT “Structural Testing and Monitoring by Fiber Optic Sensors of FRP Pedestrian Bridge in Denver O'Fallon Park”, 2002 – 2003, $110,000 (PI: B. Shing; co-PIs: Y. Xi and D.M. Frangopol).
Colorado Commission on Higher Education (CCHE) “High Toughness Rubber-Modified Concrete”, 2002 – 2003, $50,000 (PI: Y. Xi).
CDOT “Materials, Testing Methods, and Construction Practices for Fast Concrete Desk Repair”, 2003, $20,000 (PI: Y. Xi).
CDOT “Repair of Corrosion Damage and Wireless Monitoring of Corrosion Potential of Castlewood Canyon Arch Bridge in Denver”, 2003 – 2004, $120,000 (PI: B. Shing; co-PIs: Y. Xi and D.M. Frangopol).
NSF “Workshop on Interface Problems”, 2004, $15,000 (PI: K. Willam; co-PI: Y. Xi).
Sandia National Laboratory (SNL): “Structural Integrity of Reinforced Concrete Building Complexes Subjected to High Temperature”, 2004 – 2005, $27,000 (PI: K. Willam, and co-PI: Y. Xi).
FHWA “Quantify Construction Delays Due to Weather” 2004 – 2007, $110,000 (PI: Y. Xi; co-PIs: R. Balaji and K. Molenaar).
CDOT “Evaluate Performance of CDOT’s Systems for Protection of Colorado’s Reinforced Concrete Bridge Decks”, 2005 – 2007, $60,000 (PI: G. Hearn; co-PI: Y. Xi).
Tokyo Electric Service Co. “Life Prediction in AAR Affected Structures and Confined AAR Expansion Test, Phase I and Phase II”, 2007 – 2008, $105,000 (PI: V. Saouma; co-PI: Y. Xi).
National Science Foundation (NSF) “High Temperature Effects on Concrete Materials: A Multiscale Approach”, 2004 – 2008, $309,992 (PI: K. Willam, and co-PI: Y. Xi).
NASA “Refractory Materials Evaluation for Corrosion Protection of the KSC Launch Pad Flame Deflectors” $14,500 (consulting project with Kaspar Willam).
Obayashi Corp “Background Survey and Evidential Research on Concrete Temperature Limits Specified in ASME Codes” $20,000 (consulting project with Kaspar Willam).

Teaching Activities

Material Science (Undergraduate)
Mechanics of materials I (Undergraduate)
Mechanics of materials II (Undergraduate)
Statics (Undergraduate)
Concrete materials (Graduate)
Construction materials (Graduate)
Advanced mechanics of materials I (Graduate)
Advanced mechanics of materials II (Graduate)
Stability of structures (Graduate)
Infrastructure rehabilitation (Undergraduate senior and graduate)

Principal Dissertation/Thesis Advisor for Graduate Students

Graduate students obtained academic positions after graduation (6)

A.N. Ababneh, Assistant Professor, Clarkson University, Potsdam, NY.
J. Richards, Lecturer (Captain), United States Military Academy, West Point, NY.
A. Nakhi, Assistant Professor, Kuwait University, Safat, Kuwait.
M. Ghadi, Assistant Professor, University of Science and Technology of Mazandaran, Iran.
A. Asiz, Research Scientist, University of New Brunswick, Canada.
Y.S. Roh, Researcher, Dankook University, South Korea.

Ph.D. Students (15)

A. Samadi (1996 at Drexel Univ.)
Clark, Daniel (at Drexel Univ.).
Y.S. Roh (2000)
A.N. Ababneh (2002)
A. Asiz (2002)
A. Nakhi (2003)
M. Gahdi (2004, S. Stein co-advisor)
A. Suwito (2005)
J.S. Lee (2006)
E. Ou (2007, R. Corotis co-advisor)
Nattapong Damrongwiriyanupap (current)
Okpin Na (current)
Yu-Chang Liang (current)
F. Ali (current)
Pania Mashgin (current)

M.S. Students (29) (M.S. Thesis or M.S. Report)

F.E. Amparano (1995 at Drexel Univ.)
W. Xiang (1998 at Drexel Univ.).
A. Hakhi (1998)
W. Graziano (1999)
J.H. Kim (1999)
J.H. Shin (2000)
B. Black (2001)
Y.J. Cho (2002)
J.S. Lee (2002)
K. Chanvut (2002)
M.P. Blangy (2002)
Z.H. Xie (2002)
R. Cusson (2002)
K. Streeter (2002)
S. Holst (2003)
J. Richards (2004)
S.R. Deshpande (2004)
Bret Banwart (2004)
R. Sheehan (2005)
L. Abarr (2005)
J. Walbert (2005)
D. Doherty (2005)
S. Hamel (2005)
P. Orendorff (2005)
Adnan Muzaffar (2006)
M. Yamakawa (2008)
Haideh Shams Hakimi (2008)
Dustin Virgilio (2009)
Moad H. Isteita (current)

Professional Activities

Committee chairs and directors

The chair of the committee on properties of materials, ASCE/EMD, 2003-2007.
The chair of Structural Laboratory Committee, Dept. of Civil Engrg., Univ. of Colorado at Boulder.
The director of Colorado Local Technical Assistance Program.
The director of the research institute for structural engineering and structural materials, within Beijing Institute of Architectural and Construction Engineering.

Associate editor, guest editor and editorial board member of journals

A member of the advisory board for International Association on Concrete Creep (IA-Concreep) A member of the editorial board of international journal “Computers in Concrete”.
A member of the editorial advisory committee of an international journal “Concrete Science and Engineering” (RILEM).
Associate editor and Editorial Board member for Journal of Engineering Mechanics, ASCE, 2003-2007.
A member of International Scientific Committee of FraMCoS
A member of the Internal Oversight Board for the NSF NEES center at CU.
An editor for the special issue of Journal of Materials for Civil Engineering (ASCE), dedicated to Model-Based Simulation on Durability of Materials and Structures (2005).
An editor for the special issue of Journal of Engineering Mechanics (ASCE), dedicated to durability mechanics (March 2000).
An editor for the special issue of Journal of Concrete Science and Engineering (RILEM), dedicated to durability mechanics (March 2002).
An editor of the proceedings of 8th Faculty Enhancement Workshop of ACBM, July 15-18, 2001, Boulder, Colorado.

International Conferences and Workshops organized

A member of International Scientific Committee Member of FraMCoS-7, to be held in Korea in 2010.
A Scientific Committee Members of Computational Technologies in Concrete Structures, to be held in Korea in 2009.
A Scientific Committee Members of 8th International Conference on Creep, Shrinkage and Durability of Concrete and Concrete Structures, held in Sept. 2008 in Japan.
A local organizer of FraMCoS-5 (The 5th Int. Conf. on Fracture Mechanics of Concrete and Structures), April 12-15, 2004, Vail, Colorado.
An organizer of NSF Workshop on Interface Problems in Cement-Based Materials, April 12-15, 2004, Vail, Colorado.
An organizer of FHWA and CDOT Symposium on Innovative Bridge Materials and Construction, April 22-23, 2004, Denver, Colorado.
The organizer and a co-chair of the NSF Workshop on Model-Based Simulation of Durability of Materials and Structures, July 4-7, 2002, Prague.
A co-chair of the ASTM Symposium of Electrochemical Techniques to Determine Corrosion-Related Properties of Concrete and of Metals in Concrete, Committees G01 (G01.14), C09 (C09.66), June 18, 2003, Denver, Colorado.
The local organizer of 8th Faculty Enhancement Workshop of ACBM, July 15-18, 2001, Boulder, Colorado.
A member of the International Scientific Committee of CONCREEP-6, 2001, MIT, Boston.
A member of the International Scientific Committee of CONCREEP-7, 2005, Nantes, France.

Services at CU-Boulder

The executive committee member of Dept. of CEAE for SESM Group.
The coordinator of Structural Engineering and Structural Mechanics Group of CEAE in 2002 and 2003. A member of the Curriculum Committee of CEAE in 1999 and 2000.
A member of the Facility Committee of CEAE in 2001, 2002, and 2003.
The seminar organizer of Structural Engineering and Structural Mechanics Group of CEAE in 1999 and 2000.
A member of the search committee for the senior position in structural dynamics and earthquake engineering, 2004.

Member of NSF review panel, professional committees and organizations

A NSF review panelist for career proposals, Spet. 2003; SBIR proposals, March 2004; career proposals, Sept. 2004.
A member of IABMAS (International Association for Bridge Maintenance and Safety).
A member of the committee on poromechanics, ASCE/Engineering Mechanics Division.
A member of the committee on porous concrete and no-fines concrete, American Concrete Institute.
A member of the committee on experimental analysis and instrumentation, ASCE/Engineering Mechanics Division.
A member of the committee 446 (Fracture Mechanics), American Concrete Institute.
A member of the committee TC107 (Creep and Shrinkage), International Union of Testing and Research Laboratories for Materials and Structures.
A member of the committee TC QFS (Size effect of quasibrittle fracture), International Union of Testing and Research Laboratories for Materials and Structures.
A member of the committee of industrial building diagnosis & rehabilitation, National Engineering Technique Research Center, P.R. China.

Journal Articles (Peer-Reviewed)

Lee, J.S., Xi, Y., and Willam, K. (2009) “A Multiscale Model for Modulus of Elasticity of Concrete at High Temperatures”, Cement and Concrete Research, in press.
Lee, J.S., Xi, Y., and Willam, K. (2008) “Properties of Concrete after High Temperature Heating and Cooling”, J. of Materials, ACI, July-Aug. 105(4), 334-341.
Suwito, A., and Xi, Y. (2008) “The Effect of Chloride-Induced Steel Corrosion on Service Life of Reinforced Concrete Structures”, Structure & Infrastructure Engineering, 4(3), June 2008, 177 – 192.
Koller, R., Chang, S.Y., and Xi, Y. (2007) “Fiber Reinforced Polymer Bars under Freeze-Thaw Cycles and Different Loading Rates”, Journal of Composite Materials, 41(1), 5-25.
Suwito, A., Ababneh, A., Xi, Y., and Willam, K. (2006) “The Coupling Effect of Drying Shrinkage and Moisture Diffusion in Concrete”, Computers & Concrete, 3(2-3), 103-122.
Suwito, Cai, X.-C., and Xi, Y. (2006) “Parallel Finite Element Method for Coupled Chloride Penetration and Moisture Diffusion in Concrete”, International Journal of Numerical Analysis and Modeling, 3(4), 481-503.
Xi, Y., Eskandari-Ghadi, M., Suwito, and Sture. S. (2006) “A Damage Theory Based on Composite Mechanics”, J. of Eng. Mech., ASCE, 132(11), 1-10.
Li, Y., and Xi, Y. (2006) “Study on the Properties of Portland Cement Mortar and Concrete Containing Crumb Rubber Aggregate”, Concrete, 200, 45-48 (in Chinese).
Li, Y., Jin, C., and Xi, Y. (2006) “The Properties of Sulfur Rubber Concrete (SRC)”, J. of Wuhan Univ. of Tech. (Mater. Sci. Ed.), 21(1), 129-133.
Li, Y., Lee, J.S., and Xi, Y. (2005) "Study on Sulfur Rubber Concrete", J. of Building Materials, 8(4), 368-372 (in Chinese).
Xi, Y. and Nakhi, A. (2005) “Composite Damage Models for Diffusivity of Distressed Materials”, in press, will appear in June issue of J. of Materials in Civil Engineering, ASCE.
Willam, K., Rhee, I., and Xi, Y. (2005) “Thermal Degradation in Heterogeneous Concrete Materials”, in press, will appear in June issue of J. of Materials in Civil Engineering, ASCE.
Asiz, A., Zhang, W., and Xi, Y. (2003) “Analysis of Aging of Piezoelectric Crystal Resonators”, IEEE Transactions on Ultrasonic, Ferroelectric, and Frequency Control (IEEE-UFFC), 50(12), 1647- 1655.
Roh, Y.S., Asiz, A., Zhang, W.P., and Xi, Y. (2003) “Experimental Study and Theoretical Prediction of Aging Induced Frequency Shift of Crystal Resonators and Oscillators”, Microelectronics Reliability, 43(12), 1993-2000.
Xie, Z.H., Wen, X., and Xi, Y. (2003) “ ASR Potentials of Glass Aggregates in Water-Glass Activated Fly Ash and Portland Cement Mortars”, Journal of Materials in Civil Engineering, ASCE, 15(1), 67-74.
Ababneh, A., and Xi, Y. (2003) “Chloride Penetration in Non-Saturated Concrete”, J. of Materials in Civil Engineering, ASCE, 15(2), 183-191.
Xie, Z.H., and Xi, Y. (2002) “Use of Recycled Glass as a Raw Material in the Manufacture of Portland Cement”, Materials and Structures, RILEM, Sept. – Oct., 510-515.
Ababneh, A., and Xi, Y. (2002) “An Experimental Study on the Effect of Chloride Penetration on Moisture Diffusion in concrete”, Materials and Structures, RILEM, 35(254), 659-664.
Kong, J., Ababneh, A., Frangopol, D.M., and Xi, Y. (2002) “Reliability Analysis of Chloride Penetration in Saturated Concrete ”, Probabilistic Engineering Mechanics, 17, 305-315.
Suwito, A., Jin, W., Xi, Y., and Meyer, C. (2002) "A Mathematical Model for the Pessimum Effect of ASR in Concrete", Concrete Science and Engineering, RILEM, 4, 23-34.
Xie, Z., and Xi, Y. (2001) “Hardening Mechanisms of An Alkaline Activated Class-F Fly Ash”, Cement and Concrete Research, 31, 1245-1249.
Amparano, F.E., Xi, Y., and Roh, Y.S. (2000) “Experimental Study on the Effect of Aggregate Content on Fracture Behavior of Concrete”, Engineering Fracture Mechanics, 67, 65-84.
Xi, Y., Willam, K., and Frangopol, D. (2000) “Multiscale Modeling of Interactive Diffusion Processes of Concrete”, Journal of Engineering Mechanics, ASCE, 126(3), 258-265.
Roh, Y.S., and Xi, Y. (2000) “A General Formulation for Transition Probabilities of Markov Model and the Application to Fracture of Composite Materials”, Probabilistic Engineering Mechanics, 15(3), 241-250.
Meyer, C., and Xi, Y. (1999) “Use of Recycled Glass and Fly Ash for Precast Concrete”, Journal of Materials in Civil Engineering, ASCE, May, 11(2), 89-90.
Xi, Y., and Bazant, Z.P. (1999) “Modeling Chloride Penetration in Saturated Concrete”, Journal of Materials in Civil Engineering, ASCE, 11(1), 58-65.
Amparano, F.E., and Xi, Y. (1998) “Pumpability of Nonsand Concrete with Anti-Segregative Additives”, ACI Materials Journal, 95(6), 695-703.
Tennis, P., Jennings, H.M., and Xi, Y. (1997) "Mathematical Modeling of Cement Paste Microstructure by Mosaic Pattern, Part II - Application to Cement Paste", Journal of Materials Research, 12(7), 1741-1749.
Xi, Y., and Bazant, Z.P. (1997) “Random Growth of Crack with R-curve: Markov Process Model”, Engineering Fracture Mechanics, 57(6), 593-608.
Neubauer, C.M., Bergstrom, T.B., Sujata, K., Xi, Y., Garboczi, E.J., and Jennings, H.M. (1997) “Drying Shrinkage of Cement Paste as Measured in an ESEM and Comparison with Microstructural Models”, Journal of Materials Science, 32, 6415-6427.
Xi, Y., and Jennings, H.M. (1997) "Shrinkage of Cement Paste and Concrete Modeled by a Multiscale Effective Homogeneous Theory", Materials and Structures (RILEM), 30, July, 329-339.
Xi, Y. (1996) "Analysis of Internal Structures of Composite Materials by Second Order Property of Mosaic Patterns", Materials Characterization, Jan., 11-25.
Xi, Y. (1996) "Representative Volumes of Composite Materials", Journal of Engineering Mechanics, ASCE, 122(12), 1159-1167.
Xi, Y., Jennings, H.M., and Tennis, P. (1996) "Mathematical Modeling of Cement Paste Microstructure by Mosaic Pattern, Part I: Theory", Journal of Materials Research, 11(8), 1943-1952.
Bazant, Z.P., and Xi, Y. (1995) "Continuous Retardation Spectrum for Solidification Theory of Concrete Creep", Journal of Engineering Mechanics, ASCE , 121(2), 281-288.
Xi, Y., Bazant, Z.P., and Jennings, H.M. (1995) "Moisture Diffusion in Cementitious Materials: Adsorption Isotherm", Journal of Advanced Cement-Based Materials, 1, 248-257.
Xi, Y., Bazant, Z.P., and Jennings, H.M. (1995) "Moisture Diffusion in Cementitious Materials: Moisture Capacity and Diffusivity", Journal of Advanced Cement-Based Materials, 1, 258-266.
Xi, Y. (1995) "A Model for Moisture Capacities of Composite Materials - Formulation", Computational Materials Science, 4, 65-77.
Xi, Y. (1995) "A Model for Moisture Capacities of Composite Materials - Application to Concrete", Computational Materials Science, 4, 78-92.
Bazant, Z.P., and Xi, Y. (1994) "Drying Creep of Concrete: Constitutive Model and New Experiments Separating its Mechanisms", Materials and Structures (RILEM), 27, 3-14.
Xi, Y., Bergstrom, T.B., and Jennings, H.M. (1994) "Image Intensity Matching Technique: Application to the Environmental Scanning Electron Microscope", Computational Materials Science, 2, 249-260.
Bazant, Z.P., Xi, Y., and Baweja, S. (1993) "Improved Prediction Model for Time Dependent Deformation of Concrete, Part VII: Short Form of BP-KX Model, Statistics and Extrapolation of Short-Time Data", Materials and Construction, (RILEM), 26, 567-574.
Bazant, Z.P., and Xi, Y. (1993) "Stochastic Drying and Creep Effects in Concrete Structures", Journal of Structural Engineering, ASCE, 119(1), 301-322.
Bazant, Z.P., Panula, L., Kim, J.K., and Xi, Y. (1992) "Improved Prediction Model for Time-Dependent Deformation of Concrete, Part VI: Simplified Code-Type Formulation", Materials and Construction, (RILEM), 25, 219-223.
Bazant, Z.P., Xi, Y., and Reid, S.G. (1991) "Statistical Size Effect in Quasibrittle Structures: I. Is Weibull Theory Applicable ?", Journal of Engineering Mechanics, ASCE, 117(11), 2609-2622.
Bazant, Z.P., and Xi, Y. (1991) "Statistical Size Effect in Quasibrittle Structures: II. Nonlocal Theory", Journal of Engineering Mechanics, ASCE, 117(11), 2623-2640.
Xi, Y., and Bazant, Z.P. (1989) "Sampling Analysis of Concrete Structures for Creep and Shrinkage with Correlated Random Material Parameters", Probabilistic Engineering Mechanics, 4(4), 174-186.

Refereed Conference Papers

Willam, K., Lee, K.K., Xi, Y., and Lee, J.S. (2008) "Spalling of Concrete due to Combined Heating and Drying”, Creep, Shrinkage and Durability of Concrete and Concrete Structures, Proc. of CONCREEP8, Tanabe Tada-aki et al. Eds, 2, 1013-1019, CRC Press.
Lee, J.S., Xi, Y., and Willam, K. (2008) “Coupling Effect between Temperature and Moisture on the Deformation of Concrete”, Creep, Shrinkage and Durability of Concrete and Concrete Structures, Proc. of CONCREEP8, Tanabe Tada-aki et al. Eds, 2, 257 – 260, CRC Press.
Y. Xi, A. Ababneh, L. Arrar, Suwito, and X.-C. Cai (2007) “Experimental Studies and Parallel Computing on Coupled Moisture and Chloride Diffusion in Concrete”, Transport Properties and Concrete Quality – Material Science of Concrete, Special volume, Barzin Mobasher and Jan Skalny, Editors, Proc. of the Transport Properties and Concrete Quality Workshop, held in Arizona State University, Tempe, AZ., The American Ceramic Society, 41-56.
Edward, E., Xi, Y., and Corotis, R. (2007) "The Effect of Rice Husk Ash on Mechanical Properties of Concrete under High Temperatures", Proc. of 18th Engrg. Mech. Conf., held in Blacksburg, Virginia.
Ou, E., Xi, Y., and Corotis, R.(2007) "Sustainable Infrastructure Development of Guizhou Province in Southwest China: A Life Cycle Assessment of Approach", Int. Conf. on the Applications of Probability and Statistics in Civil Engineering, ICASP10, Tokyo, Japan, July 2007.
Lee, J., Xi, Y., and Willam, K. (2007) "Strength and Stiffness of Concrete under Heating and Cooling Treatments", Proc. of FraMCos6, A. Carpinteri, P. Gambarova, G. Ferro, and G. Plizarri, Editors, Vol. 2, 1709-1714.
Ababneh, A.N., and Xi, Y. (2006) "Evaluation of Environmental Degradation of Concrete in Cold Regions", Proc. of 2006 Cold Regions Conference, 10-pages, Conf. CD.
Willam, K., Basche, H., Lee, K. and Xi, Y. (2006) "Assessment of RC Bond under Severe Temperatures", Proc. Euro-C 2006, March 27-30, 2006, Mayrhofen Tyrol Austria, Computational Modelling of Concrete Structures, G. Meschke, R. de Borst, H. Mang, and N. Bicanic (eds.), Taylor & Francis Group, London, 647-656.
Willam, K., Lee, K., Lee, J. and Xi, Y. (2006) "Issues of Thermal Collapse Analysis of RCS", Structures Congress of ASCE, May 18-20, 2006, St. Louis MI, 10-page electronic paper, Conf. CD.
Willam, K., Lee, K., and Xi, Y. (2005) “Issues of Reinforced Concrete Structures under Extreme Temperature Events”, Proceedings of the 5 International Conference on Computation of Shell and Spatial Structures, E. Ramm, W. A. Wall, K.-U. Bletzinger, M. Bischo (eds.), June 1-4, 2005, Salzburg, Austria, 239-242.
Ababneh, A., Sheban, M., Suwito, A., and Y. Xi (2005) “The Coupling Effect of Drying Shrinkage and Moisture Diffusion in Concrete”, Proc. of Concreep 7, Sept. 12, Nantes, France.
Willam, K., Basche, H.D., and Xi, Y. (2005) “Constitutive aspects of high temperature material models”, fib-Workshop, Task Group 4.3.2, Fire Design of Concrete Structures, Politecnico di Milano, Dec. 2-4, 2004, 121-129.
Xi, Y., Li, Y., Xie, Z.H., and Lee, J.S. (2004) “Utilization of Solid Wastes (Waste Glass and Rubber Particles) As Aggregates in Concrete”, Proc. of International Workshop on Sustainable Development and Concrete Technology, May 20-21, Beijing, China, 45-54.
Suwito, A., and Xi, Y. (2004) “Service Life of Reinforced Concrete Structures with Corrosion Damage due to Chloride Attack”, Life-Cycle Performance of Deteriorating Structures: Assessment, Design and Management, Special Publication of ASCE, Eds., D.M. Frangopol, E. Bruhwiler, M.H. Faber, and B. Adey, 207-218.
Eskandari-Ghadi, M., Xi, Y., and Sture, S. (2004) “Composite Damage Mechanics And Applications to Modeling of Degradation of Concrete”, Fracture Mechanics of Concrete Structures, Proc. of FRAMCOS-5, V.C. Li, C.K.Y. Leung, K.J. Willam, and S.L. Billington, Editors, April, 12, Vail, Colorado, 263-269.
Eskandari-Ghadi, M., Xi, Y., and Sture, S. (2004) “The effect of heat source on upper and lower bounds of effective conductivity of anisotropic composites”, Fracture Mechanics of Concrete Structures, Proc. of FRAMCOS-5, V.C. Li, C.K.Y. Leung, K.J. Willam, and S.L. Billington, Editors, April, 12, Vail, Colorado, 507-512 .
Ababneh, A., and Xi, Y. (2003) “A New Testing Method for Determining the Coupling Effect of Chloride Diffusion on Moisture Transfer in Concrete”, Proc. of Advances in Cement and Concrete IX: Volume Changes, Crackign and Durability, August 10, Copper Mountain, Colorado, 133-140.
Willam, K., Rhee, I, and Xi, Y. (2003) “Thermal Degradation in Heterogeneous Concrete Materials”, Computational Modelling of Concrete Structures (Proc. of EURO-C 2003, St. Johann im Pongau, Austria, March 17-20, 2003), Editors: N. Bicanic, R. deBorst, H. Mang, and G. Meschke; A.A. Balkema Publishers, Lisse, 569-579.
Roh, Y.S., and Xi, Y. (2001) “The Fracture Surface Roughness of Concrete with Different Aggregate Sizes and Loading Rates”, ACI Special Publication, SP 201 - Fracture Mechanics for Concrete Materials: Testing and Applications, 35-54.
Xi, Y., Willam, K., Frangopol, D.M., Ababneh, A., Nakhi, A., Kong, J.S., and Nogueira, C.L. (2001) “Accelerated Testing and Modeling of Concrete Durability under Coupled Environmental and Mechanical Loadings”, Long Term Durability of Structural Materials, Proc. of The NSF Durability Workshop at University of California at Berkeley, Oct., Editors, P.J.M. Monteiro, K.P. chong, J. Larsen-Basse, and K. Komvopoulos, 45-56.
Ababneh, A., Xi, Y., and Willam, K. (2001) “Multiscale Modeling of the Coupled Moisture Diffusion and Drying Shrinkage of Concrete”, The Proc. of Concreep-6, MIT, in Creep, Shrinkage and Durability Mechanics of Concrete and Other Quasi-Brittle Materials, Eds. F.-J. Ulm, Z.P. Bazant, and F.H. Wittmann, Elsevier Science Ltd., 159-164.
Kong, J.S., Akgul, F., Frangopol, D.M., and Xi, Y. (2001) “Probabilistic Models for Predicting the Failure Time of Deteriorating Structural Systems”, Computational Fluid and Solid Mechanics, Proc. of the 1 st MIT Conf. on Computational Fluid and Solid Mechanics, Editor, K.J. Bathe, July 12-15, Elsevier, Amsterdam, 290-293.
Nakhi, A., Xie, Z.H., Asiz, A., Ababneh, A., and Xi. Y. (2000) “Experimental Study on Chloride Penetration under Coupled Hygromechnical Loadings”, Special Publication of ASCE “Condition Monitoring of Materials and Structures”, F. Ansari, Editor, 84-94.
Ababneh, A., Suwito, A., Xi, Y., and Abu-Hejleh, N. (2000) “A Comparative Study on Durability of Type IP and Silica Fume Concretes”, High Performance Concrete – Workability, Strength and Durability, Proc. of the Int. Sym., Editors, Leung, C., Li, Z., and Ding, J.T., Dec., Hong Kong, 273-279.
Xi, Y., and Ababneh, A. (2000) “Prediction of the Onset of Steel Corrosion in Concrete by Multiscale Chloride Diffusion”, High Performance Concrete – Workability, Strength and Durability, Proc. of the Int. Sym., Editors, Leugn, C., Li, Z., and Ding, J.T., Dec., Hong Kong, 181-186.
Gharaibeh, E.S., Hanai, T., Xi, Y., and Frangopol, D.M. (2000) “ Effects of Uncertainties on Chloride Penetration in Saturated Concrete”, Proc. of Probablistic Mechanics Conference 2000 (PMC2000), July, Notre Dame, 241-244.
Jin, W., Suwito, A., Meyer, C., and Xi, Y. (1998) "Theoretical Modeling on Expansion and Damage due to Alkali-Silica Reaction", Proceedings of 12th Engineering Mechanics Conference: Engineering Mechanics: A Force for the 21st Century, May 18-20, San Diego, CA., 1175-1178.
Roh, Y.S., and Xi, Y. (1998) " A New Formulation of Markov chain model and Application to Fracture Analysis ", Proceedings of 12th Engineering Mechanics Conference: Engineering Mechanics: A Force for the 21st Century, May 18-20, San Diego, CA., 1497-1500.
Xi, Y., Roh, Y.S., and Summers, J. (1998) "Non-destructive Testing for Fatigue Life of SMAs", Proceedings of 12th Engineering Mechanics Conference: Engineering Mechanics: A Force for the 21st Century, May 18-20, San Diego, CA., 1074-1077.
Xi, Y. (1998) "Relationship among Grain Size, Fracture Process Zone and Size Effect of Concrete", Computational Modeling of Concrete Structures, Proceedings of EURO-C, March 31 - April 3, Badgastein, Austria, Editors, R. de Borst, N. Bicanic, H. Mang, and C. Meschke, Published by A.A. Balkema, Rotterdam, the Netherlands, 275-283.
Xi, Y. (1998) " Minimum Size of Concrete Specimens for Linear Elastic Fracture Analysis", Fracture Mechanics of Concrete Structures, Vol. 3, Proceedings of FRAMCOS-3, Oct. 12-16, Gifu, Japan, Editors, H. Mihashi and K. Rokugo, Aedificatio Publishers, Immentalstr, Germany, 2021-2030.
Xi, Y., Suwito, A., Wen, X., Meyer, C., and Jin, W. (1998) "Testing and Modeling Alkali-Silica Reaction and the Associated Expansion of Concrete", Mechanics of Quasi-Brittle Materials and Structures, Proceedings of Int. Workshop in honor of Prof. Z.P. Bazant 60 birthday, March 27-28, Prague, Czech Republic, Hermes Science Publications, Paris, 217-232.
Xi, Y. (1998) "Discussion on ‘Durability Mechanics II’, Mechanics of Quasi-Brittle Materials and Structures, Proceedings of Int. Workshop in honor of Prof. Z.P. Bazant 60 birthday, March 27-28, Prague, Czech Republic, Hermes Science Publications, Paris, 435-440.
Silverstrim, T., Rostami, H., Xi, Y., and Martin, J. (1997) "High Performance Characteristics of Chemically Activated Fly Ash (CAFA)", Proceedings of the PCI/FHWA Int. Sym. On High Performance Concrete, New Orleans, Louisiana, Oct. 20-22, 135-147.
Xi, Y. (1997) "Mathematical Modeling of Chloride Penetration in Concrete", in Mechanisms of Chemical Degradation of Cement-Based Materials, Edited by K.L. Scrivener and J.F. Young, E&FN Spon, London, United Kingdom, 397-404.
Xi, Y. (1996) "Representative Volumes of Composite Materials", Proc. of 11th Engineering Mechanics Specialty Conf. of ASCE, May, Fort Lauderdale, FL, 735-738.
Xi, Y., and Amparano, F.E. (1996) "Effect of Aggregates on Fracture Process Zone of Concrete", Proc. of 11th Engineering Mechanics Specialty Conf. of ASCE, May, Fort Lauderdale, FL, 1185-1188.
Jennings, H.M., Xi, Y., Bazant, Z.P., and Yang, M. (1996) "Constitutive Characterization of Cementitious Materials based on Microstructural Models", Proc. of NATO/RILEM workshop on the Modeling of Microstructure and its Potential for Studying Transport Properties and Durability, St. Remy-les-Chevreuse, France, July 10-13, 1994, 187-226.
Xi, Y., and Bazant, Z.P. (1996) "Analysis Crack Propagation in Concrete Structures by Markov Chain Model and R-curve Method", Proc. of ASCE Specialty Conf. on Probabilistic Mechanics and Structural Reliability, Worcester, MA., Aug., 358-361.
Sujata, K., Xi, Y., and Jennings, H.M. (1996) "Interfacial Shrinkage in Mortars", in Materials for the New Millennium, Proc. of 4th Materials Engineering Conference, Nov. 10-14, Washington, D.C., 1669-1676.
Xi, Y. (1995) "Characterization of Moisture Diffusion in Concrete Based on Microstructural and Composite Models", Proc. of 10th Engineering Mechanics Specialty Conf. of ASCE, May, Boulder, Colorado, 1163-1166.
Bazant, Z.P., Xi, Y., and Baweja, S. (1995) "Solidafication Theory and Mechanisms of Aging Creep of Concrete", Proc. of 10th Engineering Mechanics Specialty Conf. of ASCE, May, Boulder, Colorado, 1372-1375.
Cheyrezy, M., and Xi, Y. et al. (1995) "Specific Production Manufacturing Issues" Chapter 2 in Proc. of 2nd Int. Workshop on High Performance Fiber Reinforced Cement Composite, June, Ann Arbor, Michigan, 25-42.
Xi, Y. (1995) "Representative Volume of Cementitious Materials", Proc. of 2nd Int. Conf. on Fracture Mechanics of Concrete and Concrete Structures, July, Zurich, Switzerland, 635-644.
Xi, Y. (1995) "A Composite Model for Moisture Capacities of Concrete", Proc. Of Int. Conf. on Concrete under Severe Conditions - Environment and Loading, August, Sapporo, Japan., 453-462.
Li, Z., and Xi, Y. (1995) “Application of Acoustic Emisson Technique to Detection of Concrete Cracking and Rebar Corrosion”, Proc. of Int. Sym. On Non-Destructive Testing in Civil Engineering (NDT-CE), Sept. 26-28, 613-620.
Bazant, Z.P., and Xi, Y. (1994) "Fracture of Random Quasibrittle Materials: Markov Process and Weibull-Type Models", Proc. of ICOSSAR, 93', Structural Safety & Reliability, Schueller, Shinozuka, & Yao (eds), Balkema, Rotterdam, 1, 609-614.
Xi, Y. (1994) "Simulation of Multiphase Spatial Distributions with Application to Fracture of Concrete", Proc. of Europe-U.S. Workshop on Fracture and Damage in Quasibrittle Structures: Experiment, Modeling and Computer Analysis, Prague, Sept., E & FN SPON, 501-510.
Bazant, Z.P., Xi, Y., and Baweja, S. (1993) "Preliminary Guidelines and Recommendation for Characterizing Creep and Shrinkage in Structural Design Codes", Creep and Shrinkage of Concrete, Proc. of the 5th Int. Symp. on Creep and Shrinkage of Concrete, Barcelona, Spain, Sept., 805-829.
Xi, Y., and Bazant, Z.P. (1993) "Continuous Retardation Spectrum for Solidification Theory of Concrete Creep", Creep and Shrinkage of Concrete, Proc. of the 5th Int. Symp. on Creep and Shrinkage of Concrete, Barcelona, Spain, Sept., 225-230.
Xi, Y., and Bazant, Z.P. (1993) "Improved Pore Water Diffusion Model for Creep Analysis of Concrete Structures", Creep and Shrinkage of Concrete, Proc. of the 5th Int. Symp. on Creep and Shrinkage of Concrete, Barcelona, Spain, Sept. 169-174.
Bazant, Z.P., and Xi, Y. (1993) "New Test Method to Separate Microcracking from Drying Creep: Curvature Creep at Equal Bending Moments and Various Axial Forces", Creep and Shrinkage of Concrete, Proc. of the 5th Int. Symp. on Creep and Shrinkage of Concrete, Barcelona, Spain, Sept., 77-82.
Jennings , H.M., and Xi, Y. (1992) "Relationships Between Microstructure and Creep and Shrinkage of Cement Paste", Material Science of Concrete, III, Ed. J. Skalny, The Amer. Cer. Soc., Westerville, OH, 37-69.
Jennings, H.M., and Xi, Y. (1992) "Cement-Aggregate Compatibility and Structure Property Relationship Including Modeling", Proc. of the 9th Int. Congress on Chemistry of Cement, New Delhi, India, Dec., 1, 663-691.
Bazant, Z.P., and Xi, Y. (1992) "Size Effect in Quasibrittle Micro-heterogeneous Structures: Deterministic and Statistical Theories", Applications of Fracture Mechanics to Reinforced Concrete, Ed. A. Carpinteri, Elsevier Applied Science, London, 1-16.
Bazant, Z.P., and Xi, Y. (1990) "Combined Spectral and Sampling Approach for Probabilistic Prediction of Creep and Shrinkage Effects in Concrete Structures", Materials Research in Concrete, Karlsruhe, May, 249-267.

Project Reports

Xi, Y., Balaji, R., and Molenaar, K. (2008) "Quantifying Construction Delays Due to Weather", Research report FHWA-CFL/TD-07-001.
Hearn, G., and Xi, Y. (2007) "Service Life and Cost Comparisons for Four Types of CDOT Bridge Decks", CDOT-2007-2, Colorado DOT, Denver, CO, 118p.
Basche. H.D., Willam, K., and Xi, Y. (2005) “Uncoupled Transient Thermo-Elastic Stress Analysis”, Internal Report CU/SESM-2005/002, University of Colorado at Boulder.
Willam, K., Xi, Y., Lee, K., and Lee, J.S. (2005) “Thermoelastoplastic Damage Analysis of RCS Subjected to Fire Scenarios”, Report to Sandia National Lab, University of Colorado at Boulder, 105p.
Fafach, D., Shing, B., Chang, S.Y., and Xi, Y. (2005) “Evaluation of the FRP-Retrofitted Arches in the Castlewood Canyon Bridge”, Colorado Department of Transportation, Report No. CDOT-DTD-R-2005-01.
Xi, Y., Chang, S.Y., Asiz, A., and Li, Y. (2004) “Long-Term Durability of Fiber-Reinforced Polymer (FRPs) and in-situ Monitoring of FRP Bridge Decks at O’Fallon Park Bridge”, Colorado Department of Transportation, Report No. CDOT-DTD-R-2004-03.
Willam, K., Xi, Y., Lee, K., Lee, J.S., and Basche, H.D. (2004) “Literature Review of Concrete and Concrete Structures Subjected to High Temperature”, Internal Report CU/SESM-2005/001 University of Colorado at Boulder, and Report to Sandia National Lab, 98p.
Xi, Y., and Li, Y. (2004) “Materials, Testing Methods, and Construction Practices for Fast Concrete Deck Repair”, Internal Report CU/SESM/XI-2004/001 University of Colorado at Boulder, and Report to Colorado DOT, 95p.
Xi, Y., Shing, B., Abu-Hejleh, N., Asiz, A., Suwito, A., Xie, Z.H., Ababneh, A. (2003) “Assessment of the Cracking Problem in Newly Constructed Bridge Decks in Colorado”, Colorado DOT Report No. CDOT-DTD-R-2003-3.
Xi, Y., Li, Y., and Li, Z.J. (2003) “High Toughness of Rubber-Modified Concrete (RMC)”, Final Report CU/SR-XI-2003/002 to The Colorado Commission of Higher Education, 63p.
Cusson, R., and Xi, Y. (2002) “The Behavior of Fiber-Reinforced Polymer Reinforcement in Low Temperature Environment Climates”, Colorado DOT Report No. CDOT -DTD-R-2003-04.
Xi, Y., Xie, Z.H. (2002) “Corrosion Effects of Magnesium Chloride and Sodium Chloride on Automobile Components”, Colorado DOT Report No. CDOT-DTD-R-2002-04.