Concrete is the most widely used material in construction industries. Therefore, it is necessary ... more Concrete is the most widely used material in construction industries. Therefore, it is necessary to understand and when possible, improve the efficiency of a concrete production process. Statistical process control is generally applied to gain information about variation in the manufacturing process. Control charts can be implemented to monitor the various processes involved in the production, the delivery and construction of concrete. When historical data are available on various projects, better insight into operational procedures ...
A closed form solution is presented for the moment-curvature response of cement-based composites ... more A closed form solution is presented for the moment-curvature response of cement-based composites with homogeneously distributed reinforcement. The derivation is based on parametric representation of uniaxial material constitutive response using piece-wise linear and quadratic segments. Effects of tensile and compressive constitutive relations on moment-curvature response were studied and it was observed that the tensile stiffness from the first cracking to the ultimate tensile strength and the ultimate tensile strain were the most ...
This paper presents design procedures for 1-D and 2-D strain hardening cement composites (SHCC) m... more This paper presents design procedures for 1-D and 2-D strain hardening cement composites (SHCC) members based on analytical models. Closed-form solutions of moment-curvature responses of SHCC are derived based on elastic perfectly plastic compressive model and trilinear strain hardening tension model. Tension stiffening behavior of SHCC due to fiber toughening and distributed cracking are considered and incorporated in the cross-sectional analysis. Load-deflection responses for beam and panel members are obtained using several different methods including moment-area, direct integration and Yield Line Theory. The proposed models provide insights in the design of SHCC to utilize the hardening properties after cracking. Using proper parameters, generalized materials model are applicable to both SHCC and strain softening cement composites such as steel fiber reinforced concrete (SFRC), textile reinforced concrete (TRC) and ultra-high performance concrete (UHPC).
The drying rate of porous materials such as hydrating cement paste during early hydration stages ... more The drying rate of porous materials such as hydrating cement paste during early hydration stages is studied using analytical and experimental procedures. Effects of micro and macro fibers as they change the nature of restrained shrinkage cracking are also documented. A methodology based on vacuum drying experiments is developed to measure the rate of evaporation from the surface of fresh paste and mortar mixtures that leads to restrained shrinkage cracking. Stages of microcrack coalescence due to plastic shrinkage cracking are quantitatively analyzed using digital image correlation. A model for internal moisture transfer simulates initial constant drying rate followed by a vapor diffusion transport phenomena. A fluid mechanics approach for water evaporation from the boundary-layer in terms of mass transfer, diffusion, and convection is used. Effect of temperature, wind speed, and relative humidity are studied. Results of these two experiments are then integrated with an analytical a...
Concrete is the most widely used material in construction industries. Therefore, it is necessary ... more Concrete is the most widely used material in construction industries. Therefore, it is necessary to understand and when possible, improve the efficiency of a concrete production process. Statistical process control is generally applied to gain information about variation in the manufacturing process. Control charts can be implemented to monitor the various processes involved in the production, the delivery and construction of concrete. When historical data are available on various projects, better insight into operational procedures ...
A closed form solution is presented for the moment-curvature response of cement-based composites ... more A closed form solution is presented for the moment-curvature response of cement-based composites with homogeneously distributed reinforcement. The derivation is based on parametric representation of uniaxial material constitutive response using piece-wise linear and quadratic segments. Effects of tensile and compressive constitutive relations on moment-curvature response were studied and it was observed that the tensile stiffness from the first cracking to the ultimate tensile strength and the ultimate tensile strain were the most ...
This paper presents design procedures for 1-D and 2-D strain hardening cement composites (SHCC) m... more This paper presents design procedures for 1-D and 2-D strain hardening cement composites (SHCC) members based on analytical models. Closed-form solutions of moment-curvature responses of SHCC are derived based on elastic perfectly plastic compressive model and trilinear strain hardening tension model. Tension stiffening behavior of SHCC due to fiber toughening and distributed cracking are considered and incorporated in the cross-sectional analysis. Load-deflection responses for beam and panel members are obtained using several different methods including moment-area, direct integration and Yield Line Theory. The proposed models provide insights in the design of SHCC to utilize the hardening properties after cracking. Using proper parameters, generalized materials model are applicable to both SHCC and strain softening cement composites such as steel fiber reinforced concrete (SFRC), textile reinforced concrete (TRC) and ultra-high performance concrete (UHPC).
The drying rate of porous materials such as hydrating cement paste during early hydration stages ... more The drying rate of porous materials such as hydrating cement paste during early hydration stages is studied using analytical and experimental procedures. Effects of micro and macro fibers as they change the nature of restrained shrinkage cracking are also documented. A methodology based on vacuum drying experiments is developed to measure the rate of evaporation from the surface of fresh paste and mortar mixtures that leads to restrained shrinkage cracking. Stages of microcrack coalescence due to plastic shrinkage cracking are quantitatively analyzed using digital image correlation. A model for internal moisture transfer simulates initial constant drying rate followed by a vapor diffusion transport phenomena. A fluid mechanics approach for water evaporation from the boundary-layer in terms of mass transfer, diffusion, and convection is used. Effect of temperature, wind speed, and relative humidity are studied. Results of these two experiments are then integrated with an analytical a...
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