We use the three carson dunlop associates sketches shown here to comment on the occurrence causes and significance of cracks and movement in poured concrete slab construction.
Measuring cracks in concrete.
Hc 2940 concrete crack width gauge.
Horizontal cracks in concrete walls however indicate poor wall designs or pressure buildup behind the wall.
As stated in your question aci 224 1r 07 recommends two devices for measuring crack widths.
Steel ruler is simple instrument used to monitor crack width variation.
Hc 2939 concrete crack gauge displacement.
If a vertical crack widens at the top or bottom the wall is either settling or gradually heaving which may present serious issues.
18 00 crack width monitor.
A crack comparator a small hand held microscope with a scale on the lens closest to the surface being viewed.
The vibrating wire crack meter a re used to measure movement across surface cracks and joints in concrete rock soil and structures.
Crack width grading ruler.
In impact echo test a stress pulse is generated at the surface of the element.
And a clear card with lines of various widths.
This applies to oppose tensile forces to the lower part of the drying concrete on the surface causing a cracked concrete profile.
The following are the instruments used to monitor crack width variations.
Hc 2942a concrete crack monitor adhesive.
19 00 crack width grading ruler.
A simple yet accurate device for monitoring movement in a crack change in crack width movement up down.
Methods to monitor crack width changes in concrete.
Displacement crack gauge monitors horizontal and displacement movement.
Precision hand made product designed specifically for measuring concrete cracks.
While evaluating a concrete structure accurate determination of crack widths will help in identifying the possible causes and if needed repair methods for cracks.
Designed to measure widths and locations of cracks prior to crack monitoring program.
Before we describe crack movement and damage patterns and diagnosis in concrete slabs we need to introduce three different types of poured concrete floor slabs.
If the crack widths are smaller than the listed widths there probably is not a structural problem.
Crack depth measurement in concrete i.
Stair step cracks may also signify heaving.
Visual examination of concrete cores.
The committee lists several methods of measuring crack width but from the sound of your problem the best tool to use is a comparator.
If larger you may need to call in an expert.
Brass screws and caliper.
Extracting core samples from the defects is considered a popular method among.
After measuring the cracks you can determine whether they are tolerable by referring to table 1 in aci 224 control of cracking in concrete structures which lists tolerances for cracks in reinforced concrete.
Concrete walls containing horizontal cracks are serious issues.
