جستجوی مقالات مرتبط با کلیدواژه "fine-grained" در نشریات گروه "عمران"

The use of industrial waste, such as steel slag, in the road construction industry, to reduce the use of stone materials and also the environmental benefits of reusing these materials is very important. Research on the use of steel slag as an alternative to stone materials in asphalt pavements has been carried out for many years due to the improvement of some of the main properties of these mixtures. In these researches, slag in general (including fine-grained and coarse-grained with the same percentage) or coarse-grained has replaced the stone materials. However, since some properties of asphalt mixtures show different effects by changing the fine-grained materials or a different combination of fine-grained and coarse-grained to the simultaneous and equal replacement of fine-grained and coarse-grained, in this research, optimum percentage of using slag materials in fine-grained and coarse-grained size has been investigated using the response surface method. In this regard, different mixing schemes of this substitution have been investigated using modulus of resistance, Marshall resistance, indirect tension and moisture sensitivity tests. Results of the performed experiments and their analysis has determined the type of fine-grained and coarse-grained behavior in asphalt mixtures, and finally, for each experiment, the proposed model has been determined based on the research conditions.

The use of porous concrete system in urban areas as a modern and applied management approach during rainfall can prevent the problems by rapid outflow of the surface runoff. In this research, effect of replacing dolomite minerals in two modes of fine-grained and powder, as part of the aggregates or part of the cement, respectively, is investigated on the structural properties of porous concrete. In order to use porous concrete in urban runoff management system, the compressive strength and porosity should be considered. Two series of samples were made for structural experiments. The 15×15×15 cm samples were designed to test the compressive strength and the 10×10×10 cm samples were made to determine the porosity percentage. Statistical analyses of the laboratory results were performed using SPSS software. According to the results, replacement of dolomite powder for cement did not have significant effect on compressive strength and porosity. On the other hand, fine-grained dolomite has greatly improved the compressive strength. In addition to increasing the compressive strength, the porosity was increased due to the mechanism of particle placement in samples receiving 10% fine aggregates. Also adding 30% fine grained, increased compressive strength by 162%. This is while the porosity percentage has fallen sharply.

Modern methods of reinforcing walls were used in the 60sby Henry Vidal. Reinforced soil wall is an alternative toretaining walls and traditional embankments. The useof geosynthetics as reinforcement in reinforced soil wallshas been signi cant in recent years. Reinforced soil wallshave been used in Iran since 70s. Accordingly,in someareas, due to the lack of access to suitable materialsand high cost of material supply from far zones, ne-grained soils may be used for wall back ll. Reinforcedslopes and walls come with various applications, includ-ing its use in bridge abutment. In this study, the e ectof ne-grained soils, strip surcharge, and wall angle onbehavior of geosynthetic reinforced soil walls using cen-trifuge modeling has been studied. In this study, a set of8 centrifuge testes on saturated ne-grained walls rein-forced with geotextile was performed using the geotech-nical research center of Iran University of Science andTechnology centrifuge, and behavior of physical modelsusing digital image processing technique was studied.The comparison between place of rupture on geotextileand slid surface obtained from digital image processingwas a good matched. Therefore, combination of cen-trifuge modeling with digital image processing is a goodway to study the behavior of geosynthetic reinforced soilwalls.The results showed that with increasing load of stripfooting, the amount settlements of top of wall increased,and this e ect on vertical walls is more than the batteredwalls. Moreover, stains of reinforced layers and defor-mation of facing wall also increase when nes in back llincreased from %10 to %20. It was observed that slidesurfaces were entry from behind of strip footing and de-veloped to the toe of the walls. With increasing percentof ne-grained in back ll from %10 to %20, sliding sur-faces were deeper. In addition, with the decreasing ofangle of face, the models were stable. In addition, exis-tence of %10 nes in sand back ll improves performanceof geosynthetic reinforced soil wall (GRSW). If nes inthe back ll increased to %20, GRSW would have poorperformance.