concrete has a special place at the current century; it has been and is the most widely used building material. producing concrete has several environmental impacts that should be considered to prevent consequent problems. in recent years, several methods have been developed to produce concrete that is compatible with the environment and sustainable development basis. in these concretes, beside...

semiconducting carbon nanofibers (cnf) are prepared from three different sources, i.e., acetylene, ethanol, and cotton by the chemical vapor deposition (cvd) process. these fibers are having rich elastic, engineering and conductivity properties. fresh self-compacting concrete (scc) flows into place and around obstructions under its own weight to fill the formwork completely and self-compact, wi...

In this study, first by surveythe parameters affecting the compressive strength, such as water to cement ratio, cementgrade, silica fume to cement percentage, and the various ratios oflight weight aggregate LECA, to total aggregate, Taguchi method is used, to test 9 mix designsobtained the mix design optimization. Since lightweight concrete is brittle like normal concrete, to resolve this probl...

There is a worldwide interest in using fibers of different types in concrete mixtures. In this regard, as the use of PET fibers has gradually increased during the last decade, this study aims to investigate the effects of PET fibers on the mechanical properties of hardened concrete and the workability of fresh concrete. To this end, different contents of PET fibers (PC= %0, %0.5, %1 and %1.5) a...

In the present study, a new method for retrofitting reinforced concrete beam is introduced in which steel-concrete composite jackets containing steel fiber is used. For this purpose, 75% of the peripheral surface of reinforced concrete beams was initially reinforced using steel plates and bolts, and steel fiber reinforced concrete was used between the steel plates and the peripheral surfaces of...

hot or cold weather condition affects the quality of the concrete in different ways, which one of them is increase or decrease in the initial temperature of the concrete. in this study, the impact of the initial temperature of the concrete on its quality in concrete kerbs made by dry pressing method with portland cement is examined. concretes with similar mix designs and initial temperatures of...

Adding steel braces to reinforced concrete frames is a common way for seismic rehabilitation of these structures. Due to ease of installation and the possibility of creating openings in the braced bays, this method of rehabilitation has been more preferred than using shear walls. In this paper, three experimental specimens including a reinforced concrete frame, a reinforced concrete frame with ...

Lightweight concrete (LWC) is a kind of concrete that made of lightweight aggregates or gas bubbles. These aggregates could be natural or artificial, and expanded polystyrene (EPS) lightweight concrete is the most interesting lightweight concrete and has good mechanical properties. Bulk density of this kind of concrete is between 300-2000 kg/m3. In this paper flexural strength of EPS is modeled...