HJC黄金城

The KM series strain transducers are designed to measure strain in materials such as concrete, synthetic resin which undergo a transition from a compliant state to a hardened state. Their extremely low modulus (KM-M:25N/mm²) ,(others:40N/mm²) and waterproof construction are ideally suited for internal strain measurement during the very early stages of curing. They are totally impervious to moisture absorption, producing excellent stability for long-term strain measurement. Relative temperature measurement is also possible with the KM-B. The built-in thermocouple sensor of the KM-BT enable actual temperature measurement in addition to strain measurement. Adding to the above embedment use, surface strain measurement onto concrete, H-beam steel is also available with various optional fittings.
The new KM-M type small-diameter strain transducer has a smaller diameter than the conventional product and is suitable for measuring concrete with a thin cover thickness and surface strain. The KM series is compliant to CE marking except for KM-50F and KM-M.

Protection ratings : IP 67 equivalent for KM-30 / IP 68 equivalent for KM-50F to KM-100BT and KM-M

Features

• Self-temperature compensated transducer having a linear thermal expansion coefficient similar to concrete
• Low elastic modulus enables inner strain measurement during the very early stages of curing
• Simultaneous measurement of strain and temperature except for KM-30 ,KM-50F
• Surface strain measurement is also available onto retaining wall, strut, sheet pile, etc.
• KM-30/KM-100B/-100HB/-100BT Only CE Marking Complian

Specifications

For Internal Strain Measurement

The KM Strain Transducers make possible strain measurement in materials such as concrete which undergo transition from a compliant state to a hardened state. The KM is designed to measure various strains produced by external force, ambient temperature, drying shrinkage, materials creep, etc. Applicable gauge length should be three times as large as the diameter of the aggregate so as to give an averaged evalsuation of the concrete. 

An installation onto the reinforced concrete structure

As illustrated below, the KM end is wired between reinforcing bars, then position the KM to marked points of reinforcing bar in advance.

An installation onto the Non-stress meter case

The KM strain transducer is placed in a Non-stress meter case (KMF-51) and installed into the concrete structure, where the coefficient of linear expansion and shrinkage strain of the concrete are determined by the strain value and the temperature measured by the in-built temperature measurement function.
The Non-stress meter case (KMF-51) with KM transducer is secured to reinforcing bars near the installation locations using strapping wires to avoid shifting during concrete placement.
If there is no rebar near the mass concrete, install the rebar and secure it without causing any structural problems.

An installation onto the pavement

During pavement construction, driving tests, loading tests, and longperiod deterioration tests are conducted using various types of sensors.

For surface strain measurement

Surface strain measurement onto steel and concrete structures is available with KM-100B or KM-100BT.

 (Optional fittings such as Spacer and Collar are available for fixing the model and positioning gauge length.

An installation onto the surface of steel structure

The KM model is combined with optional Collar KMF-22-100 to install onto the surface of steel by welding.

An installation onto the surface of concrete structure

The KM model is combined with optional Collar KMF23B-100 to install onto the surface of concrete structure with anchor bolts.

Temperature measurement function

Transducers with built-in temperature measurement function include strain gauge type and thermocouple type. The former uses a three-wire quarter bridge (350Ω) to measure relative temperature, while the latter can measure actual temperature with a thermocouple.
In both types, accurate measurements can be made using the measuring instrument; compared with using other thermometers alone, installation and wiring work can be greatly simplified.
Built-in temperature measurement function (strain gauge type): KM-100B/KM-100HB
Built-in temperature measurement function (thermocouple type): KM-100BT

KMF Optional accessory

Surface strain measurement onto steel and concrete structures is available with KM-100B or KM-100BT. (Optional fittings such as Spacer and Collar are available for fixing the model and positioning gauge length.)