# Abrasion-Resistant and Temperature Control of
## 2 Anti-Scouring and Abrasion-Resistant Performance Test on Concrete
### Materials, Mix Proportions, and Test Method
#### 2.2.3 Test Method  
The test was performed according to the ring method using a high-velocity water flow abrasion-resistance apparatus as the test device, shown in Figure 3[25]. The test mold was a cone on the outside, 30 cm in inner diameter and 10 cm in height. After the preparation, the concrete specimen was placed in the quiescent state at room temperature for 24 h; after that, it was demolded and moved into a standard curing chamber at 20 \(\pm\) 5 \({}^{\circ}\)C and \(>\)95% relative humidity for curing purpose. The specimen was soaked in water for saturation 2 day before reaching the test age and then taken out of the water, wiped and weighed for the scouring and abrasion test.  
The scouring and abrasion medium used emery with a particle size in the range of 0.4-2.0 mm and a sand factor of 20% (mass ratio). The water flow had a nominal flow rate in the range of 10-40 m/s (freely adjustable) and was set at 40 m/s in this test. The specimens in each group were subjected to repeated scouring and abrasion for three times; the cumulative scouring and abrasion time was \(T\). After the test, each specimen was taken out, flushed with water, wiped and weighed again. The anti-scouring and abrasion-resistant strength of concrete was calculated using the following formula [25]:  
\[f_{a}=\frac{TA}{\Delta M} \tag{1}\]  
where \(f_{a}\) represents the anti-scouring and abrasion-resistant strength of concrete, i.e., the time taken to scour and abrade a unit of mass on a unit area, h/(g/cm\({}^{2}\)); \(T\) represents the cumulative scouring and abrasion time of a specimen, h; \(A\) represents its scoured area, cm\({}^{2}\), (\(A=\pi DH\)); \(D\) represents its inner diameter, 30 cm; \(H\) represents its inner ring height, 10 cm; \(\Delta M\) represents the cumulative scouring and abrasion mass during \(T\) time interval, g.  
A standard cubic specimen with an edge length of 150 mm was used, and each group consisted of three concrete blocks made and cured under the same conditions. The uniaxial compressive strength was expressed by the pressure per unit area when the specimen was damaged, as shown in Formula (2). The tensile strength of concrete was determined by splitting method, as shown in Formula (3).  
\[f_{cu}=\frac{F}{A} \tag{2}\]  
where \(f_{\text{cu}}\) is the compressive strength of concrete cube (MPa), \(F\) is the ultimate load (N) and \(A\) is the compression area (mm\({}^{2}\)).  
\[f_{\text{ts}}=\frac{2F}{\pi A} \tag{3}\]  
where \(f_{\text{ts}}\) is splitting tensile strength of concrete (MPa), \(F\) is failing load (N) and \(A\) is the area of splitting surface of specimen (mm\({}^{2}\)).  
Figure 3: A high-velocity water flow abrasion-resistance apparatus.  
The dry shrinkage deformation of concrete is expressed by the shrinkage rate. The specimens of 100 mm \(\times\) 100 mm \(\times\) 500 mm were dried and shrank to the specified age under standard test conditions. The length of specimens before and after drying shrinkage was measured and the readings were repeated three times during each measurement. Taking the arithmetic mean value of the three measurements, the dry shrinkage rate can be calculated according to Formula (4).  
\[\varepsilon_{st}=\frac{L_{0}-L_{t}}{L_{b}}\times 100\% \tag{4}\]  
where \(L_{b}\) is measuring gauge length of test piece; \(L_{0}\) is the initial value of specimen length; \(L_{t}\) is the length value of the test piece measured at test period T (mm); \(\varepsilon_{st}\) is the dry shrinkage rate of concrete obtained when the test period is t days.