Purpose of Test

Many of the more than 171,000 bridges in Japan were constructed over 50 years ago. Bridges, especially those located in an area with heavy snowfall, are exposed to tough condition. In this case study, Concrete Tester (CTS-02v4) was used to assess compressive strength of a bridge slab in Hokkaido, where they have the coldest winters and heaviest snowfall in Japan, with 6 months out of the year hovering around freezing and an average snowfall around 9-10 inches.

Man using concrete tester on a concreate celling
Measurement Scene

Measurement Procedure

Some parts of the bridge slab were in danger of collapsing due to frost damage. Measurement points were arranged at constant intervals (200mm x 100mm) to assess current compressive strength distribution of the slab. An inspector strikes 3 times at each point with CTS-02v4, and the average value was used to evaluate the compressive strength at each point.

Contour map of where the flaws of the concrete are
Figure 1: Measurement Result

Results of the Test

Measurement results are shown as Figure 1. Red lines in the figure shows cracks on the slab. Compressive strength tends to be lower where cracks are clustered together. Although apparent critical damage was not observed, partial repair was conducted to maintain the durability of the slab.

Advantage of CTS-02v4

There are several types of NDT equipment for compressive strength estimation such as the rebound hammer, impact elastic wave method, or ultrasonic wave method. CTS-02v4 was selected for this case because it is easy to use and systematically and efficiently measures compressive strength and deterioration compared to other NDT equipment.

Nitto CTS Vol 1
Download PDF • 423KB

Want to see CTS in action? Curious to try it out for yourself? Questions about the product?

Reach out to us and we would love to help!

We are happy to announce that an article on our study on concrete testers is now available at, an established resource for construction industries.

“A Study on Estimating Concrete Compressive Strength by Mechanical Impedance” is an in-depth analysis of the theoretical background of reactive mechanical impedance measurement and results of laboratory and field tests on compressive strength estimation of concrete.

Click the link below for the whole article.

New product Release: We will launch CTS-03 BOLT-Tester in the US market later in July.  By simply tapping bolts or nuts with a dedicated hammer, the BOLT-Tester measures the waveforms of rebound force by a built-in impulsive accelerometer. If the reactive motion is considered as elastic behavior, bolts or nuts are evaluated as integrity while plastic behavior is evaluated as non-integrity so that you can find the loosening of bolt & nuts. Please find the details