Investigating the Possibility of Using Recycled Asphalt Pavement (RAP) and Steel Slag as a Substitute for Part of the Materials in Roller Compacted Concrete (RCC) Pavements

Recycling is one of the most important issues in the construction industry in the world. Today, it is common to use different types of concrete in construction projects. One of these types of concrete is Roller Compacted Concrete (RCC), which has advantages such as fast and easy construction, lower construction costs and resistance in hot weather conditions and heavy loading. This concrete can be used in the construction of road pavements and all kinds of massive structures. In this study, the effect of replacing reclaimed asphalt pavements (RAP) as coarse aggregates and steel slag as fine aggregates with different percentages has been investigated on the mechanical properties of roller concrete. Samples were cured for 7 and 28 days after mixing design. The results of tests show that with increasing the replacement of RAP and steel slag in RCC samples, the compressive strength is significantly reduced; Compressive strength in the sample containing 100% RAP and steel slag, is approximately one third of the compressive strength of the sample; However, this declining trend has slowed down for the tensile and flexural strengths. Also, only the sample containing 25% of RAP and steel slag has the required minimum compressive strength in accordance with the relevant standards; While 28-day tensile and flexural strength in samples containing 25%, 50% and 75% of RAP and steel slag, is higher than the allowable values ​​in accordance with the relevant standards. The results of toughness test showed that with increasing RAP and steel slag, the maximum load was decreased; However, energy absorption capacity and consequently toughness increased, due to the increase in flexibility of RCC mixtures.