Zhao Yan-na

Bio: Zhao Yan-na is an academic researcher from Chang'an University. The author has contributed to research in topics: Durability & Bundle. The author has an hindex of 1, co-authored 2 publications receiving 8 citations.

Relationship between Pore Structure of Concrete and Its Frost Durability Degradation

Abstract: Pore-measuring method and mercury intrusion method based on digital technology can detect the hole structure of cement concrete with the aim to ascertain the relationship between frost durability degradation of cement concrete and pore structure. Meanwhile the influence of pore structure on the anti-frost performance is analyzed. The results show that additive like excellent air-entraining agent can obviously perfect the pore structure of cement concrete so that the anti-frost performance is heightened.

Development of Continuous Beam Bridge Steel Bundle Optimization System

Abstract: The prestress steel bundle optimization model established on the basis of mathematics planning means,the strands arrangement system and the drawing system of prestress construction document based on object-oriented technology and programming method,these realizes the incorporation of continuous beam bridge design calculation and drawing construction document It can emancipate the designers from the troublesome work,and guarantee the design quality,shorten design period

Durability Studies on the Recycled Aggregate Concrete in China over the Past Decade: A Review

Abstract: Since China hosted the Olympic Games in 2008, a mass of construction and demolition (C&D) wastes were produced with the rapid urbanization construction. Recycling the C&D waste into recycled aggregates (RA) is an effective method for reducing the amount of C&D wastes. Many studies on the properties of RA and the durability of recycled aggregate concrete (RAC) were conducted in China over the past decade. Due to the restrictions of various languages, some valuable studies on the durability of RAC are hard to be acquired by the scholars around the world. Therefore, this paper is developed to review the studies on the durability of RAC in China, and the shrinkage behavior, chloride permeability, carbonation behavior, and freeze-thaw resistance of RAC are, respectively, introduced. Considering the waste concrete, bricks, and ceramics used in preparing RA are frequently mixed together in China, this study proposes an index of average water absorption rate to quantify the effects of RA types, quality, and replacement percentages on the durability of RAC. Meanwhile, the relationship between the average water absorption rate of RA and the durability parameters of RAC is established. Finally, the improving methods of RAC durability are introduced, and the RA particle shaping and carbonation modification are emphasized.

A stochastic damage model for evaluating the internal deterioration of concrete due to freeze–thaw action

Abstract: This paper presents a stochastic damage model for evaluating the internal deterioration of concrete due to freeze–thaw action, which involves great uncertainty and randomness. In this model, the structural element of concrete is discretized into infinite microelements, whose lifetimes are assumed to be independent random variables. Then expressions for the mean and variance of the damage of concrete are analytically derived. To calibrate the model parameters, a series of freeze–thaw tests in water on non-air-entrained concrete were conducted and back-calculation analyses were performed on the test results of dynamic modulus. The reliability of the proposed stochastic damage model is further validated through comparisons with the results of 80 other existing test specimens. The present model offers a theoretical basis for exploring the statistical aspect of concrete behavior during freeze–thaw.

The Correlation between Pore Structure and Macro Durability Performance of Road Concrete under Loading and Freeze-Thaw and Drying-Wetting Cycles

Abstract: The grey correlation theory and multiple regression method are used to reveal macro performance degradation rules of road concrete under loading and freeze-thaw and drying-wetting cycles; then the correlation between mesoscopic pore structure and residual strength and antifreezing index of concrete is analyzed. Under the freeze-thaw and drying-wetting cycles with 50% loading level, the pore structure parameters that influence concrete strength show the following sequence: fractal dimension > most probable pore size > porosity > less harmful pore. The correlation between strength and pore parameters can be represented with multiple nonlinear equations. A negative correlation is shown between strength and fractal dimension and most probable pore size. Conversely, a positive correlation is shown between strength, porosity, and less harmful pore. Under the freeze-thaw and drying-wetting cycles with 80% loading level, the pore structure parameters that influence concrete strength show another sequence: fractal dimension > porosity > less harmful pore > most probable pore size. The correlation between antifreezing index and pore parameters should be described with multiple linear equations. The relative dynamic elastic modulus shows a positive correlation to most probable pore size, pore surface area, and porosity but a negative correlation to less harmful pore and pore spacing coefficient.

Volcanic activity and thermal excitation of rich-silicon iron ore tailing in concrete

Abstract: In order to distinguish the filling effect and volcanic activity and explore the ways motivating the activity of rich-silicon iron ore tailing(IOT), inert quartz was brought in as the correction standard, the influences of fineness, calcination, thermal curing system and some other factors were investigated by IR, XRD, MIP, and so on microscopic methods. The experimental results show grinding and calcination can only change the amorphous state of SiO2, and IOT do not have volcanic activity in concrete cured under room temperature condition. Thermal curing systems can stimulate the activity of IOT, especially mortar cured by autoclave curing system can consume a large amount of Ca(OH)2 and hard calcium silicate and has a closer structure. When the specific surface area of IOT powder is 800 m2/kg, and 30% cement is replaced by IOT powder, the mortar strength with IOT powder is even higher than that with cementonly.