Washer Glenn, Fuchs Paul, Graybeal Benjamin A, Hartmann Joseph Lawrence
Federal Highway Administration, Turner Fairbank Highway Research Center, McLean, VA 22101, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2004 Feb;51(2):193-201.
Concrete is a critical material for the construction of infrastructure facilities throughout the world. Traditional concretes consist of cement paste and aggregates ranging in size from 6 to 25 mm that form a heterogeneous material with substantial compressive strength and a very low tensile strength. Steel reinforcement is used to provide tensile strength for reinforced concrete structures and as a composite the material is useful for structural applications. A new material known as reactive powder concrete (RPC) is becoming available. It differs significantly from traditional concrete; RPC has no large aggregates, and contains small steel fibers that provide additional strength and, in some cases, can replace traditional steel reinforcement. Due to its high density and lack of aggregates, ultrasonic inspections at frequencies 10 to 20 times that of traditional concrete inspections are possible. This paper reports on the initial findings of research conducted to determine the applicability of ultrasonic testing techniques for the condition assessment of RPC. Pulse velocities for shear and longitudinal waves and ultrasonic measurement of the modulus of elasticity for RPC are reported. Ultrasonic crack detection for RPC also is investigated.
混凝土是全球基础设施建设中的关键材料。传统混凝土由水泥浆和粒径为6至25毫米的骨料组成，形成一种抗压强度高但抗拉强度极低的非均质材料。钢筋用于为钢筋混凝土结构提供抗拉强度，作为一种复合材料，该材料在结构应用中很有用。一种名为活性粉末混凝土（RPC）的新型材料正逐渐问世。它与传统混凝土有显著不同；RPC没有大骨料，包含小钢纤维，这些钢纤维可提供额外强度，在某些情况下还能替代传统钢筋。由于其高密度且无骨料，能够以比传统混凝土检测频率高10至20倍的频率进行超声检测。本文报告了为确定超声检测技术对RPC状态评估的适用性而开展的研究的初步结果。报告了RPC的剪切波和纵波脉冲速度以及弹性模量的超声测量结果。还对RPC的超声裂纹检测进行了研究。
