In this study, the co-operation of steel and concrete in composite columns is considered. Using numerical modeling to study the behavior of these sections, a new type of sections, namely Concrete Filled Double-Skin steel Tubular (CFDST) columns, is introduced. The parameters and techniques that influence the numerical simulation that bring this modeling closer to...

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...

fiber reinforced polymers (frp) have widely used for the purposes of enhances strength and ductility of concrete columns. proper design of such hybrid columns, however, requires a better recognition of the behavior of concrete columns confined with frp. in this paper, the influence of frp thickness, concrete compressive strength, and column size on the performance of eccentrically loaded reacti...

this paper deals with the interfacial effects of silica fume (sf) and styrene-butadiene polymer (sbr) on compressive strength of concrete. analyzing the compressive strength results of 32 concrete mixes performed over two water-binder ratios (0.35, 0.45), four percentages replacement of silica fume (0%, 5%, 7.5%, 10%) and four percentages of sbr (0%, 5%, 10%, 15%) were investigated. a mathemati...

Silica fume has been largely used in concrete in recent decades due to its effect on improvement of strength and &#10durability of concrete. On the other hand, attention has been recently paid to the use of limestone powder as a substitute for part of cement in concrete, basically because of its low price and its positive effect on the durability of concrete. The aim of the current study is the...

Some Problems on High Strength Concrete for Prestressing by Kanji YAMAZAKI (Research Laboratory of Nihon Cement Co., Ltd., Tokyo) This paper describes some problems on high strength concrete studied in our laboratory in recent years. Summary of this report is as follows: (1) In order to make high strength concrete for prestressing, it is necessary to lower the water-cement ratio. But, in the ca...

In this paper, using sewage sludge carried out to manufacture high performance ceramsite. At the same time, the performance of concrete made from sewage sludge ceramsite was analyzed. The results show that the ceramist is mainly composed of cristobalite and mullet, and has dense enamel structure on surface and honeycomb closed fine porous structure in internal. Too large ceramsite size can caus...

Ultra-high performance concrete (UHPC) is a developing concrete and today is increasing to interest using it in structures due to its advantages such as high-compressive strength, modulus of elasticity, highly durability and low-permeability. Therefore, it is necessary to provide models for prediction of nonlinear behavior of this material. This study is aimed to investigate the tension-stiffen...

This paper describes sixteen fire tests conducted on slender circular hollow section columns filled with normal and high strength concrete, subjected to concentric axial loads. The test parameters were the nominal strength of concrete (30 and 80 MPa), the infilling type (plain concrete, reinforced concrete and steel fiber reinforced concrete) and the axial load level (20% and 40%). The columns ...