Gauges refine sand, slab moisture measurement
- Published: Friday, 22 April 2011 13:22
- Written by CP Staff
European concrete testing specialists offer devices suited to North American practitioners
The HD2 mobile sand and gravel moisture meter puts an end to the inconvenience of the laborious kiln-drying and intricate CM test, according to German developer Imko GmbH. The unit enables quick verification of the moisture content of delivered sand or gravel, or checking aggregate moisture regarding suitability for further processing.
Product engineers describe HD2 as a handy and robust system for the quick determination of the moisture content in sand and gravel, as well as other aggregates. For the actual measurement, the robust two-rod probe PICO64 is connected to the HD2. Probe rods are inserted into the material and measurement is performed with the push of the start button. Within two seconds, the moisture measurement value is presented on the clear display.
In contrast to the kiln-drying method, where the measurement is usually restricted to a 3- to 5-liter moisture volume, or the CM test, which measures approximately 50 ml, Imko engineers note, the HD2 is able to provide the user with a moisture content value of 1.25 liters’ volume with only one measurement. In the “Average Value” operation mode, six readings are sufficient to provide the measurement of a material volume of 7.5 liters within a few seconds.
The PICO64 measures with the new TRIME (Time-Domain-Reflectometry) radar technology. The PICO64 gauges water content to the point of material saturation and beyond via an electro-magnetic pulse with 1-GHz frequency. — www.imko.de
Officials of Switzerland’s Proceq cite an advanced product development commitment behind the new Hygropin Moisture Meter, contending the technology represents the most accurate and least invasive method to quickly identify concrete floor slabs’ moisture content. Excess moisture in concrete hampers floor covering installation. To prevent mildew and major damage, the flooring industry requires precise technology to check concrete for moisture prior to installing coverings or coatings. The moisture content inside the concrete is different than that on the surface, where testing methods only measure up to 3/4-in. deep at best.
The Proceq Hygropin is reportedly the only moisture meter to utilize simultaneously both in-situ and ambient probes. The combination offers precise interior measurement of relative humidity and concrete slab temperature. The in-situ technique has proven to be the most reliable method of moisture testing since it measures directly where the moisture hides below the surface of the concrete, Proceq engineers contend.
With a 5-mm diameter, the small in-situ probe minimizes damage to the concrete surface. The ambient probe, directly connected to the instrument, simplifies the capturing of environmental parameters. The Hygropin is able to display the results of these two independent sensor channels showing ambient and concrete characteristics simultaneously, calculating psychrometric parameters and the difference between the values measured by the two probes.
“The Proceq Hygropin concrete moisture meter’s small sensor minimizes damage to the surface and reduces the installation efforts immensely. With an accuracy range of ±1.5 percent relative humidity, the Hygropin is able to deliver measurements to the finest degree,” says Paul Siwek, marketing manager for Gurneed, Ill.-based Proceq U.S.
With the small air volume of the measuring sleeve and fast reaction time of the in-situ probe, the Hygropin is able to deliver stable values within five minutes. The Hygropin is reportedly the only moisture meter to display when stable temperatures and humidity values are reached to prevent false readings caused by insufficient equilibration time.
Proceq provides complete service and technical support through its global network and support facilities. The Hygropin is backed by Proceq’s standard two-year warranty on all electronic parts with an extended warranty option available.
Company’s 2011 catalog features equipment for material producers, contractors and engineers involved in nondestructive testing of concrete, mortar, masonry brick and other building materials. It references instruments to determine strength, locate objects in structures, evaluate density ultrasonically, analyze corrosion, as well as determine moisture content. Equipment categories span a number of parameters:
Material strength. The Windsor Probe System for compressive strength measurement in the field suits conventional and high performance concrete. The device conforms to ASTM C 805, C 803, and other international standards, and includes the Windsor Pin System for measuring the strength of new or existing concrete, mortar and other construction materials utilizing the established principle of resistance to penetration. A unique chuck allows testing of mortar joints' compressive strength in the field.
The catalog also offers manual test hammers for economical, quick and easy concrete compressive strength test in the field. They provide indices of hardness and compressive strength for other construction materials, and conform to ASTM C-805 and other international standards. Digital test hammers afford quick and easy determination of concrete strength, and hardness of construction materials. Like the manual test hammers they also conform to ASTM C 805.
The James Bond Test System measures the bonding strength between two layers of existing materials, determining the adhesion strength of shotcrete, epoxies, paint and other repair materials or coatings. The Standard Anchor Test System measures the pull strength of anchors in concrete, wood, masonry, brick and other construction materials. The Super Anchor Test System for testing anchor strengths in concrete, wood, masonry, and other construction materials above 40KN (4,000 lb.). Also included in this category is IQM Meter System, which enables fresh concrete strength to be easily and completely monitored in the field for improved safety, quality, and optimum setting time, while recording time and temperature.
Rebar locators. The primary instrument is the R-Meter MK III, an advanced system for finding the location, depth, and size of reinforcement bar, post tension cables, copper and conduit. The unit includes a cover-mapping feature, storage, and image upload to PC. Also included is the handheld Mini R-Meter, ruggedized for tough field use, and suited to pinpointing rebar and estimating either the depth or size of the reinforcement, post tension cables, copper and conduit.
Ultrasonics. Category includes the V-Meter MK III measuring ultrasonic pulse velocity in concrete and other coarse-grained construction materials. The device locates cracks, voids, rot and other inconsistent or problem-prone areas in the material under test. Conforming to ASTM C 597, the system includes transducers, instrumentation unit, cables and software for PC.
The ASTM C 1383-conforming Vu-Con System for measuring the thickness, determining quality, and locating areas of honeycombing, voids and delaminations in concrete includes instrumentation unit, velocity and depth transducers, impactor set, charger and PC software for data uploads. The E-Meter MK II is used for the determination of resonant frequency of materials, Young's modulus of elasticity, and Poisson's ratio; system includes E-Meter Instrument, Accelerometer w/ Pick-Up Cable, Charger, Rs 232 Cable, PC Software, and Standard Bench Assembly w/ Parts.
Corrosion. Category has a range of instruments for engineers, including the Gecor 8 for corrosion rate determination. It can rapidly map a structure's rebar corrosion rate with an advanced modulation confinement technique for precise analysis. The device also has a new corrosion rate analysis technique for use in wet or submerged structures, plus a new methodology for measurement of cathodic protection efficiency.
The Chlorimeter, a field test system to determine the chloride ion concentration in wet or dry concrete, automatically shows a temperature compensated reading of percent of chlorides on its digital display. A wide chloride range—from 0.002 to 2 percent chloride by weight—is covered. The Cor-Map and Cor-Map II half-cell potential systems identify areas of probable corrosion in the field.
The Poroscope performs a field test for air and water permeability of concrete using the Figg technique. Permeability both at the concrete surface as well as within the concrete mass can be determined, along with porosity in sealants and surface mortars. The Ohmcorr Test System concrete resistivity meter is used to assess rebar corrosion in concrete. Additional offerings are the James ASTM Type B pressure and Volumetric air meters.
Moisture determination. The Trident is a microwave meter used for the rapid determination of moisture content in sand and other fine or coarse aggregates. The Aquaprobe and Cementometer are microwave devices to determine moisture content in different types of soil and water/cement content ratio in fresh concrete, respectively. — www.ndtjames.com