aquaculture is among the oldest occupations of human being. over the past quarter of century, the aquaculture industry has grown rapidly. the effect of water containing sodium sulfate on long term compressive strength of concrete of fishing ponds and channels is investigated in this paper. aim of this paper was to analyze the strength of concrete channels and of aquaculture which are in direct ...

Nowadays, the better performance of lightweight structures during earthquake has resulted in using lightweight concrete more than ever. However, determining the compressive strength of concrete used in these structures during their service through a none-destructive test is a popular and useful method.  One of the main methods of non-destructive testing in the assessment of compressive strength...

The strength of concrete is a function of the proportions of the constituent materials, namely, cement, water, fine and coarse aggregates. The conventional methods used to determine the mix proportions that will yield the desired strength, are laborious, time consuming and expensive. In this paper, a mathematical method based on modified regression theory is formulated for the prediction of con...

The addition of steel fibers into concrete improves the postcracking tensile strength of hardened concrete and hence significantly enhances the shear strength of reinforced concrete reinforced concrete beams. However, developing an accurate model for predicting the shear strength of steel fiber reinforced concrete (SFRC) beams is a challenging task as there are several parameters such as the co...

In this study, the benefits of limestone powder (LP) and marble powder (MP) as partial replacement of Portland cement are established. Furthermore, LP and MP are used directly without attempting any additional processing in the production of selfcompacting concrete (SCC). The water to binder ratio is maintained at 0.33 for all mixtures. The examined properties include workability, compressive s...

the current research intends to study the possibility of producing fiber recycled self-compacting concrete (frscc) using demolitions as a coarse aggregate (crushed red brick and crushed ceramic). steel fibers were used in recycled self-compacting concrete (rscc) to improve fresh and hardened properties of this type of concrete. thirty nine concrete mixes were prepared to achieve the aim propose...

Silica fume has been largely used in concrete in recent decades due to its effect on improvement of strength and durability 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 i...

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...