recent tendencies in concrete technology have been towards to high- performance concrete with a low water-cement ratio. however, high performance concretes have some problems. one of the problems is early-age cracking due to autogenous shrinkage. this study presents the results of an experimental investigation carried out to evaluate the autogenous shrinkage of high-strength concrete. accordin...

with many years of construction and application of common concrete, researchers have always been searching for a better composition. one of the notable ideas for achieving such a composition is using recycled materials. one of the materials which is suitable for environment and constant development is damaged tires .for studying mechanical properties of concrete containing tire particles, a ser...

steel corrosion of bars in concrete structures is a complex process which leads to the reduction of the cross-section bars and decreasing the resistance of the concrete and steel materials. in this study, reliability analysis of a reinforced concrete beam with corrosion defects under the distributed load was investigated using the enhanced hasofer-lind and rackwitz-fiessler (ehl-rf) method base...

this paper reviews some progressive studies and innovations in cement and concrete materials in nano field. due to the widespread acceptance of the special properties of nano materials and using them for engineering concrete performance, understanding and directing their properties are not achievable without instructing concepts and investigating interactions among components. due to achievemen...

ABSTRACT  Introduction: Recently uses of medium and high energy x-rays has been increased in Iran and radiotherapy centers along with a variety of accelerators have been installed in some provinces. In the other hand there is no sufficient skill in designing and making radiotherapy treatment rooms. This study was conducted to evaluate the efficacy of different m...

Given the development of construction industry and design and implementation of high rise buildings with complex sections and various geometrical forms, the use of self-compacting concretes has received the attention of construction engineers and provided great advantages. Due to the increasing air pollution in cities, governments encounter the important issue of repelling the pollutants in whi...

Quantum secure direct communication protocols offer confidential transmission of classic information over the quantum channel without a prior key agreement. The ping-pong based protocols provide asymptotic security and detailed analysis of the security level provided by each variant of the protocol is required. The paper presents a general method of calculation of the eavesdropped information a...

A mathematical model for the description of drying shrinkage of autoclaved aerated concrete (AAC) is presented, bringing together the hygrothermal and mechanical considerations. The verification of the model is done using an approximation of a real laboratory experiment. Then, the applicability of the model is demonstrated by a numerical simulation of drying shrinkage and wetting expansion of A...

Cryptographic puzzles (or client puzzles) are moderately difficult problems that can be solved by investing non-trivial amounts of computation and/or storage. Devising models for cryptographic puzzles has only recently started to receive attention from the cryptographic community as a first step toward rigorous models and proofs of security of applications that employ them (e.g. Denial-of-Servi...

For more than 100 years, the primary theme underlying the NBS/NIST staff contribution to the crystallography of building materials has been the development of an improved understanding of concrete materials performance. Over that time period, portland cement concrete has become one of the most important of our construction materials for roads, buildings, and other large municipal structures. At...