The wear resistance of concrete is affected by the strength properties of the aggregate and the compressive strength, porosity and contact area of the concrete. As the porosity of the concrete increases, the contact area decreases and the stress on the contact area increases, resulting in rapid wear of the top surface. At this stage, the compressive strength of the aggregate plays an important role in the wear of the concrete top surface.
Other factors affecting the wear resistance of concrete are the hardness of the aggregate and the quality of the bond between the aggregate and the slurry. Furthermore, the bond between aggregate and slurry is affected by the shape, texture, gradation and firmness of the aggregate. Surface mortars are very sensitive to moisture content, and the quality of the grout and fine aggregate affects its wear resistance.
Published literature shows that the wear resistance of concrete is reduced when CBA is used as a sand substitute. It is believed that CBA granules have a lower hardness compared to natural sand grains, and that the porous microstructure of CBA granules makes concrete more resistant to moisture than conventional concrete. These are the main reasons for the decrease in wear resistance of concrete with CBA. Uxel et al.
(2007) showed that due to the higher iron content (13%) in CBA, the wear values of concrete containing CBA as a substitute for sand were lower than the upper limit value of 13/50 cm2 given in TS 2824 and ASTM C 936 Given 15/50 cm2. According to the study, the porosity of concrete containing up to 20% CBA is not high, and the contact area is sufficient to reduce the stress on the top surface. But when the replacement level exceeds 20%, the porosity of concrete increases, the contact area decreases, and the compressive strength of aggregate particles exceeds.
A higher loss of mass therefore occurs. Experimental studies by Singh and Siddique (2015a,b) also showed that the average wear depth of concrete incorporating low calcium CBA increases with increasing CBA content. However, according to BIS: 1237-2012 Heavy-duty ceramic tiles, the average wear depth of concrete made with CBA is less than the specified 2 mm wear depth, with a wear time of 7.5 minutes. According to this study, the wear resistance of concrete containing CBA increases with age, similar to that of ordinary concrete. Continued hydration and densification of the concrete microstructure with age may be responsible for increased wear resistance. According to this study, the average wear depth of concrete incorporating CBA as a sand replacement decreased almost linearly with increasing compressive strength. At 28 days of age, the CBA content in concrete varied with wear depth.
Experimental studies by Ghafoori and Bucholc (1997) also showed that concrete mixtures containing 356 and 474 kg/m3 cement content exhibited 47.5% and 35.2% higher average wear than ordinary concrete when containing 100% CBA as a sand substitute depth. Concrete is controlled separately. However, the concrete mixture containing 50% CBA and 50% sand as fine aggregate showed about 13% higher wear resistance compared to the control concrete.
The study by Aramraks (2006) confirmed the concept of reduced wear resistance of concrete when CBA was added as a sand substitute and showed that concrete containing 100% CBA lost 3.29 times the weight of normal concrete in wear tests. According to this study, concrete containing 50% CBA instead of sand and 2% superplasticizer was the more suitable concrete, both in terms of abrasion resistance and compressive strength.
Another experimental study by Ghafoori and Bucholc (1996) showed that the wear resistance of concrete incorporating 100% high calcium CBA was 40% lower than that of control concrete. Published literature shows that the wear resistance of concrete incorporating CBA as a sand substitute is improved when WRA is used. According to Ghafoori and Bucholc (1996), the abrasion resistance of concrete made with 100% CBA exceeds that of control concrete after adding WRA.
Another study by Ghafoori and Cai (1998b) using RCC made of 100% CBA as a sand substitute showed that the wear depth of concrete decreased with increasing cement content. RCCs made from CBA showed excellent abrasion resistance in air-dry conditions compared to wet conditions. In wet conditions, RCCs made with CBA showed 7.25 times greater wear depth than in air-dried conditions. However, as the cement content was increased from 9% to 12% and 15%, the ratios decreased to 6.42 and 6.00, respectively, indicating that higher cement content produced stronger slurries and smoother surface layers.
