摘要
为了研究长龄期对混凝土构件超声波速与回弹值的影响,制作了三组不同强度等级(C20、C30、C40)的混凝土构件(尺寸为2 400 mm× 400 mm × 2 400 mm),在龄期为4 d、7d、14 d、28 d、90 d、180 d、365 d、730 d、951 d、1 350 d、1 730 d时进行回弹值和超声波速检测,并对检测结果进行数据分析和线性拟合,研究回弹值和超声波速与龄期之间的关联.结果表明:混凝土构件的回弹值和超声波速度随着龄期的增长呈现先快后慢的趋势,在超过一年后基本保持稳定.在强度等级小于等于C30时,随着强度等级的增加,回弹系数的增长速率也随之增大;而在强度等级大于C30时,趋势相反.此外,混凝土构件的回弹值与超声波速度呈正相关关系,但存在一定的阈值,超过该阈值后回弹值和超声波速度均趋于稳定,不再显著增长.
Abstract
To study the effects of long-term aging on the ultrasonic pulse velocity and rebound values of concrete components,three groups of concrete specimens with different strength grades(C20,C30,C40)and dimensions of 2,400 mm × 400 mm × 2,400 mm were prepared.Rebound values and ultrasonic pulse velocity were tested at aging periods of 4 days,7 days,14 days,28 days,90 days,180 days,365 days,730 days,951 days,1,350 days,and 1,730 days.Data analysis and linear fitting were performed to investigate the correlation between rebound values,ultrasonic pulse velocity,and aging.Results show that rebound values and ultrasonic pulse velocity increase rapidly in the early stages of aging but gradually stabilize after one year.For strength grades C30,the growth rate of the rebound coefficient increases with the strength grade;for strength grades＞C30,the trend reverses.Additionally,rebound values and ultrasonic pulse velocity exhibit a positive correlation,though a threshold exists beyond which both parameters stabilize and no longer increase significantly.
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