Record the steady transit time reading; repeat on a grid to map the element.<\/li>\n<\/ol>\nCalculation & Reporting<\/h2>\n
Velocity V = L \/ T (km\/s), where L is path length and T transit time. Report arrangement, path length, and any surface conditions. For indirect readings, apply the standard’s correction as surface measurements read 5–20% lower.<\/p>\n
Acceptance Criteria<\/h2>\n
Common quality bands for natural-aggregate structural concrete: above 4.5 km\/s excellent; 3.5–4.5 km\/s good; 3.0–3.5 km\/s doubtful; below 3.0 km\/s poor. Bands are indicative \u2014 compare against sound areas of the same structure and mix.<\/p>\n
Frequently Asked Questions<\/h2>\nCan UPV give compressive strength directly?<\/h3>\n
No. Velocity-strength correlations are mix-specific and moisture-dependent. Combine UPV with rebound hammer (SonReb method) or cores when strength values are required.<\/p>\n
Does reinforcement affect readings?<\/h3>\n
Yes \u2014 steel transmits pulses about 1.7 times faster than concrete. Route pulse paths away from bars parallel to the path, or apply the correction factors given in the standards.<\/p>\n
Recommended Apparatus<\/h2>\n
NL Scientific manufactures the Ultrasonic Detector<\/a> for this method. Browse the full Concrete Testing Equipment<\/a> range or request a quotation<\/a> from our engineers.<\/p>\n
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