# Assessing Abrasion Resistance in Concrete Pavements: A Review
## 4 Factors Affecting Abrasion Resistance
### Influence of Material Properties
#### 4.1.5 Use of Recycled Aggregates  
Recycled Concrete Aggregate (RCA) has been shown to have lower abrasion resistance than natural aggregates [52]. In comparison to fresh aggregate, which had an abrasion loss of less than 20%, an investigation into the use of recycled aggregate on continuously reinforced concrete pavement revealed a loss of approximately 32-38% [25].  
When compared to virgin aggregate, RCA often exhibits less resilience to abrasion mass loss (American Concrete Pavement Association, Rosemont, IL, USA, 2020). Particle movement under cycling loading causes the aggregate in the pavement to abrasively wear down. Over time, this may cause the properties of the aggregate to decline, particularly in low-quality RCA that contains crushed bricks. By stabilizing the aggregate with geogrid,aggregate abrasion was decreased because there was a significant decrease in displacement and particle rotation under cyclic loads [53]. The abrasion resistance is decreased as determined by the Micro-Deval or Los Angeles coefficient. The reduction is contingent upon the original concrete's grade and the size of its aggregates. Because the abrasion loss falls within the allowed range of 22% to 40% and complies with ASTM C-33 and BS 882 1201 Part 2 standards of 30% to 50%, it should be highlighted that this is not a concern for RCA [54].  
The Bohme disc was used to evaluate concrete samples with and without RCA after 91 days. The results showed that the application of RA had no effect on the abrasion resistance, with thickness losses of roughly 3.5 and 4.5 mm for coarse RCA and both coarse and fine RCA mixes, respectively. However, as compared to the complete or partial substitution of both fine and coarse NA, mixes containing only fine RCAs performed the worst, with abrasion resistance reductions of 40% to 47% [55]. A study using the ASTM C131 test on the use of recycled concrete aggregate in CRCP showed that the LA abrasion value was between 32 and 38% and could be used as a supplement for natural aggregate to economize pavement construction [56].  
Traffic loads, construction, and the properties of the RCA mixture all affect how resistant RCA concrete pavement is to surface wear and aggregate polishing. The RCA will not always polish and turn slick but it may become visible due to wear and/or grinding. RCA concrete is likely not going to cause any problems with skid resistance if the aggregate used in the source concrete is not linked to any problems [57]. When traffic loads are applied to RCA concrete in jointed plain concrete pavement, the faces of transverse joints or mid-slab cracks are more susceptible to abrasion, which causes a quick loss of load transfer capacity at these sites. Compared to using traditional coarse aggregates, the RCA's paste portion's poor abrasion resistance causes larger and faster losses in load transfer [52]. A concrete pavement reconstruction project on the I-10 in Texas, where RCA was used in the concrete mix, showed higher values of abrasion of 32-38% (test method ASTMC131) compared to natural aggregate, which usually has abrasion values of less than 20% [58].  
Ref. [PERSON] [37] examined the impact of adding recycled concrete aggregates to concrete mixes with two distinct weight-to-composite ratios of 0.44 and 0.38 at an age of 28 days by exposing the specimens to air-driven silica sand impingement and calculating the mass loss. The author concluded that RCA lowers abrasion resistance by 18% to 22%. For blends containing fine RA, the reduction was greater. Nonetheless, the RA's abrasion resistance was sufficient for its application in the construction of concrete pavement.