جستجوی مقالات مرتبط با کلیدواژه « مصالح خرده آسفالت » در نشریات گروه « عمران »

Massive amount of debris and trashes, one of the issues and problems of today's world is the especially asphalts debris resulting from the removal of worn-out pavements of urban roads. Recycled asphalt crumbs are waste materials that certainly have significant undesirable effects on the surrounding environment. Given the properties reported by these materials, there are various ways to reuse these materials. One of the applications that have been considered by researchers is the use of these materials in cement mixtures, including concrete production. This is while that a large amount of asphalt fragment is continuously produced in the repair and maintenance of roads. It is therefore desirable to be used in conventional mixtures used in Construction of roads pavement. In this regard, the present study investigates the performance Evaluation of Roller Compacted Concrete Pavement make by Recycled Asphalt using Micro Silica with the aim of reducing waste and its negative impacts on the environment. By examining the documentation and performing numerous experiments, it has been found that roller compact concrete made from recycled asphalt can be used as a suitable pavement for low traffic and rural roads, as well as for the final covering of a wide range of sidewalks. It is also suitable as CBT.

In this study, the effect of the use of two WMA additive sasobit and rheofalt additives on the fatigue properties of the asphalt mixes was evaluated. For this purpose, laboratory samples containing 100 % RAP and a hot mixture were constructed using RAP material, which is separated from the bitumen. The recycled mixtures include a hot recycling sample and three warm (1 non - additive sample, 1 sample containing sasobit additive, 1 containing rheofalt additive). In this research, different experiments such as indirect tensile strength, resilient modulus and fatigue are investigated. Fatigue test was performed on four - point bending test with constant strain level at three levels 600, 800 and 1000 micro - strain with sinusoidal loading. The fatigue life of specimens was evaluated based on a 50 % reduction in the initial hardness modulus. The results showed that sasobit and rheofalt additives had a positive effect on the compression and functional properties of the blends. In the performance of fatigue and low - temperature cracks, the hot mixture was better in spite of the positive effects of additives.

The use of Reclaimed Asphalt Pavement (RAP) helps us save our natural resources and money. Of the different types of asphalt pavements that can be built, HMA pavements are considered the best in the terms of strength and durability. But the production temperature limits the amount of RAP used in the new mixture because this production`s high temperature requirement causes the deterioration of the aged binder of RAP and increases greemhouse gas emission. In the recent years there has been much focus on Warm Mix Asphalt (WMA) technology, because the aim of this approach is to reduce the production temperature by using additives which increase the workability of the binder at a lower temperature. The use of WMA additives helps us reduce the temperature while preserving the desired workability, thus enables HMA to contain higher percentages of RAP. The purpose of this experimental study was to evaluate the effect of production temperature reduction by using WMA additives on the performance properties of asphalt mixture containing 100% RAP. To reach this goal, five mixes were prepared and tested: a control mix (100% RAP-mixing temperature 150°C), three mixes with Sasobit, Rheofalt and without additives (mixing temperature of 130°C), and one virgin mix with extracted aggregate (mixing temperature of 160°C). The performance properties of the mixtures were evaluated based on indirect tensile strength, resilient module, four point beam fatigue test, and dynamic creep test etc. The results showed that the mixtures with WMA additives had better performance according to their moisture susceptibility and rutting potential, but the control mix had better performance in fatigue and low temperature cracking.