Evaluation and Comparison of Real-Time Laser and Electric Sand-Patch Pavement Texture-Depth Measurement Methods

In order to measure the texture depth of asphalt pavement automatically and accurately, a data set generated by a real-time laser pavement texture meter (RLPTM) was realized, and a calculation method was developed. Three groups of experiments were designed and conducted to calibrate the measure results of the electric sand patch method (ESPM) to the ASTM sand patch method and compare the performance of the RLPTM with the ESPM. Experimental results showed that the correlation coefficient of the ESPM and sand patch method have reached up to 0.9830, indicating a good correlation. The RLPTM method had higher resolution (more significant figures) and better repeatability (lower coefficients of variation) than ESPM. The correlation coefficient between RLPTM and ESPM was 0.9207, demonstrating the good repeatability of the overall measurements. The absolute errors of the results obtained by RLPTM and ESPM were within 0.3mm. Further analysis indicated that results of RLPTM were slightly over predicted (slope value 1.0141) compared to that of ESPM, whereas results of ESPM were slightly under predicted (slope value 0.9823) to that of sand patch. Thus, results of RLPTM may come closer to ASTM sand patch data than ESPM data, indicating the high accuracy of RLPTM.