Day visibility is the luminance coefficient under diffuse illumination (from the sun or urban lightning). This principle is important in road...

Day visibility is the luminance coefficient under diffuse illumination (from the sun or urban lightning). This principle is important in road safety. Vehicles drivers must be able to see the road markings and signs . A retroreflectometer is used to measure the day visibility performance of the surface. The day visibility (written “Qd”) is measured in mcd. m^-2. lx^-1

The adhesion of a coating on a substrate is crucial for the mechanical performance as well as for the corrosion protection. In practice, there are...

The adhesion of a coating on a substrate is crucial for the mechanical performance as well as for the corrosion protection. In practice, there are several test procedures for determining the adhesion such as cross-cut test, mandrel test and impact test.

The cross-cut test is a very rapid and simple method for the assessment of single and multi-coat systems. Here, cuts in a 30° angle (method A) or right-angle (method B) are executed so that you receive a lattice pattern or an X-shape. These test methods can be used as quick pass/fail tests. When applied to a multi-coat system, assessment of the adhesion of individual layers of the coating among each other may be carried out.

The ZCC2087  Cross-cut tester or the ZCT2067 Crooss-cut Templet can be used to perform an cross-cut test.

The most typical data collection is when the Tx-Rx pair (Transmitter and Receiver of the GPR antenna) moves in parallel with the line that you are...

The most typical data collection is when the Tx-Rx pair (Transmitter and Receiver of the GPR antenna) moves in parallel with the line that you are collecting data. When the antenna is in its standard position, metallic targets will appear brighter than non-metallic ones. That leads to radargrams with very bright metallic targets and very weak non-metallic targets. Sometimes, the reflection from the metallic targets can disguise completely any reflection from nonmetallic ones or can hide the bottom of the concrete slab. This way of data collection is often called in-line data collection. 

In order to see non-metallic targets clearer, an antenna can be reversed by 90 degrees to the line (make diagram). Now, the scan is more sensitive to the non-metallic targets. Metallic targets will appear less bright than during the in-line data collection. Concrete slab bottom will also become clearly visible. This way of data collection is called cross-polarized data collection or cross-polarization.

There are many rebound hammer correlation curves freely available for different lithologies to be found in literature on the internet. e.g. Aydin,...

There are many rebound hammer correlation curves freely available for different lithologies to be found in literature on the internet. e.g. Aydin, A. & Basu, Arindam. (2005). The Schmidt Hammer in rock material characterization. Engineering Geology. 81. 1-14. 10.1016/j.enggeo.2005.06.006.

Most of these curves were created with classical R-value hammers and can be used entered directly as a custom material curve in the Original Schmidt Live app.

To use with the RockSchmidt it is necessary to convert to a Q-value curve. Typically the Q-value is R-value + 10.

e.g. Katz et al. (2000)

UCS = 2.21e(0.07R)

Using the R-value curve and the corresponding Q-value it is a simple matter to derive the Q-value curve using the trendline function in spreadsheet software.

UCS = 1.0975e(0.07Q)

There are various standards that describe the execution of a cross-cut test in order to determine the adhesion of a coating.

Method A: for tests...

There are various standards that describe the execution of a cross-cut test in order to determine the adhesion of a coating.

Method A: for tests in accordance to ASTM D3359 (for thicknesses >125µm)  and DIN EN ISO16276-2 for all films 

or

Method B (lattice pattern) for tests in accordance with DIN EN ISO 2409 with thickness 0µm - 250µm and ASTM D3359 (for thicknesses <125µm)

In order to execute a cross-cut test the following procedure is followed:

1. Intersecting cuts (6 cuts with the appropriate spacing, depending on the method and the film thickness) are performed. With Method A the intersecting cuts are at an angle of 30° (X-cut) and with method B the intersecting cuts are at an angle of 90° (lattice pattern).
2. In order to produce these cuts a dedicated cross-cut tester as the ZCC2087 can be used, or alternatively a sharp blade with the appropriate cross-cut templet (ZCT2160). The cross-cut tester is specifically designed to produce a reproducible pattern. Note: Always pull the cross-cut tester.
3. Clean the  cut pattern with a soft brush (included in the cross-cut tester).
4. Place an adhesive tape over the lattice parallel to one set of cuts. Ensure good contact with the coating.
5. Evaluate the pattern according to the selected standard.

NOTE: Using an adhesive tape is not a normative reference. Therefore it's possible to use any adhesive tape. However we suggest to use a tape with an adhesive strength on steel between 6N and 10N. As the adhesive strength on coatings can differ to the tape manufacturer's specification on steel. Therefore it is important to always use the same adhesive tape in order to get reproducible results. (e.g. our ACC753 with an adhesive strength on steel of 10N).

Using an adhesive tape is not a normative reference. Therefore it's possible to use any adhesive tape.

However we suggest to use a tape with an...

Using an adhesive tape is not a normative reference. Therefore it's possible to use any adhesive tape.

However we suggest to use a tape with an adhesive strength on steel between 6N and 10N. As the adhesive strength on coatings can differ to the tape manufacturer's specification on steel. Therefore it is important to always use the same adhesive tape in order to get reproducible results. (e.g. our ACC753 with an adhesive strength on steel of 10N).

Retroreflection, also called night visibility, is a specific type of light reflection when the light rays goes on a surface and comes back to the...

Retroreflection, also called night visibility, is a specific type of light reflection when the light rays goes on a surface and comes back to the source of light. This principle is a pillar in road safety. Indeed, the vehicles lamps during the night enable to see the road markings, road signs and conspicuity tapes. A retroreflectometer is used to measure the retroreflection performance of the surface. The retroreflection (often written “R”) is measured in mcd. m^-2. lx^-1.