瓯越大桥混凝土超声回弹综合法专用测强曲线

摘要

In order to develop the non-destructive test technology of concrete strength for OuyueRiver Bridge, a series of experiments were carried out to investigate the influences of mixing ways (single-mixed and double-mixed) of fly ash and ground slag on the relationship of concrete rebound values and representativevalue of ultrasonic velocity with compressive strength. Then, the special strength curves of ultrasonic−rebound combined method for concrete of Ouyue River Bridge were established based on the test results with normal rebound instrument and high-strength rebound instrument, respectively.The reliability of special strength curves was verified by the field test.The resultsshowthat mixing ways of fly ash and ground slag have no influences on the relationship of concrete rebound values and representativevalue of ultrasonic velocity with compressive strength when the content of fly ash is less than 35% and the content of ground slag is less than 50%. The strength curve equation of ultrasonic−rebound combined method with normal rebound instrument and high-strength rebound instrument can be used to carry out non-destructive test to the concrete with a strength grade ofC35~C80 and C50~C80,respectively.%为解决瓯越大桥混凝土强度无损检测技术，通过试验系统研究单掺、双掺粉煤灰和矿粉对混凝土回弹值、声速代表值与抗压强度关系的影响，分别建立使用普通回弹仪和高强回弹仪时的瓯越大桥混凝土超声回弹综合法专用测强曲线，并通过现场试验验证所建立专用测强曲线的可靠性。研究结果表明：当粉煤灰最大掺量为取代35%的水泥用量，矿粉最大掺量为取代50%的水泥用量时，掺合料类型和掺加方式对混凝土回弹值和声速代表值与抗压强度的关系均无显著影响；使用普通回弹仪和高强回弹仪建立的超声回弹综合法专用测强曲线公式分别适用于对强度等级为C35~C80和C50~C80的同类混凝土进行强度无损检测，使用方便，且具有较高精度。