1.1 该试验方法涵盖了纹理的连通性，因为它与路面通过其表面和地下孔隙的排水能力有关。这是一种特定的设备，可以计算已知量的水在重力作用下通过被测结构路面纹理中的空隙逸出所需的时间。该技术旨在提供路面从车辆轮胎表面释放压力的能力的测量，从而提供在潮湿条件下潜在的水上滑行的指示。更快的逸出时间表明轮胎和路面之间可能存在更薄的水膜，因此可能会暴露出更多的微观纹理，从而使轮胎表面凹陷，并使轮胎产生更多的表面摩擦。 排空水所需的秒数越低，轮胎下的水压就越低。将由操作员将该试验结果与其他相关因素进行比较，如预期降雨强度和频率、骨料类型、质地一致性、坡度、坡度、预期车速和事故历史，以确定出流表读数与在给定表面上滑水可能性之间的关系。在所有其他因素相似的情况下，将已知有滑水历史的路面的流出表读数与有良好历史的路面进行比较，将为操作员提供促进潮湿天气安全所需的流出表编号指示。 1.2 使用该试验方法获得的结果与铺砌表面的平均水力半径有关，并可能与其他测量纹理的方法相关。 1.3 使用该测试方法获得的结果与平均纹理深度（MTD）有关。 1.4 以国际单位制或英寸磅单位表示的数值应单独视为标准。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。将两个系统的值结合起来可能会导致不符合标准。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 该试验方法适用于现场试验，以评估路面面层的表面排水，在某些情况下，还适用于路面面层内部排水。当与其他试验一起使用时，流出时间可用于评估沥青混凝土混合料产生的纹理、硅酸盐水泥混凝土路面上使用的修整方法以及旧路面表面的修整操作。 测试结果将与其他方法相关，如CT测量仪（测试方法 E2157 )，MPD（实践 E1845 )和MTD（测试方法 E965 ). 注1: 流出时间的倒数与MPD高度相关，除非表面是高度多孔的，因为MPD是表面纹理的度量，并且不考虑流过表面孔隙的水。 5.2 通过该方法测量的流出时间仅为指示，并不意味着提供路面表面摩擦或潮湿天气安全特性的完整评估。 5.3 该试验方法不一定与其他测量路面表面特性的方法相关或一致。由操作员决定所考虑的每种方法的相关性。

1.1 This test method covers the connectivity of the texture as it relates to the drainage capability of the pavement through its surface and subsurface voids. This is a specific device that times how long it takes a known quantity of water, under gravitational pull, to escape through voids in the pavement texture of the structure being tested. The technique is intended to provide a measure of the ability of the pavement to relieve pressure from the face of vehicular tires and thus an indication of hydroplaning potential under wet conditions. A faster escape time indicates a thinner film of water may exist between the tire and the pavement, thus more micro-texture could be exposed to indent the face of the tire and more surface friction available to the tire. The lower the number of seconds it takes to evacuate the water, the lower the water pressure under the tire. It will be up to the operator to compare the results of this test to other pertinent factors such as expected rainfall intensity and frequency, aggregate type, consistency of texture, grade, slope, expected vehicular speed, and accident history, to determine the relationship between the outflow meter reading and the likelihood of hydroplaning on a given surface. Comparing the outflow meter reading of a pavement known to have a history of hydroplaning, against one with a good history, with all other factors similar, will give the operator an indication of the outflow meter number that will be necessary to promote wet weather safety. 1.2 The results obtained using this test method are related to the mean hydraulic radius of a paved surface and may correlate with other methods to measure texture. 1.3 The results obtained using this test method are related to the mean texture depth (MTD). 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method is suitable as a field test to evaluate the surface drainage, and in some cases, the internal drainage of the surface course of a pavement. When used with other tests, the outflow time may be used to evaluate the texture produced by an asphalt concrete mix, a finishing method used on portland cement concrete pavement, and refinishing operations on an old pavement surface. Test results will correlate with other methods such as the CT Meter (Test Method E2157 ), MPD (Practice E1845 ), and MTD (Test Method E965 ). Note 1: The reciprocal of the outflow time is highly correlated with the MPD except when the surface is highly porous, since the MPD is a measure of the surface texture and does not account for the water flowing through the surface pores. 5.2 The outflow times measured by this method are an indication only, and are not meant to provide a complete assessment of the pavement surface friction, or wet weather safety characteristics. 5.3 This test method does not necessarily correlate or agree with other methods of measuring pavement surface characteristics. It is up to the operator to determine the correlation of each method considered.