There are a variety of manufacturers on the market that offer a large range of the concrete testing equipment in association with fresh concrete. Some of these machines include shrinkage-determination testing machines, rheometers for paste and mortar and rheometers used for fresh concrete and air entrainment meters.
The Air Entrainment Meter
Air Entrainment Meters are used to measure air content in the freshly-mixed motor that is associated with the principle of air-pressure compensation. This machine uses a pressure-chamber where a predefined-pressure is created. Once the overflow-valve has been opened, this pressure will be compensated about the test-pot that contains the mixed mortar. The drop in pressure is then measured to define the air-content inside this mortar.
Air entrainment can be described as the deliberate production of bubbles of air in mortar or concrete. Water typically becomes trapped in this mixture as it begins to harden. This water will eventually evaporate which results in a porous cavity. These particular pores are what result in a weakness in mortar or concrete during the stages of freeze and thaw cycles. Air entrainment meters are used to measure the air trapped in the mix. The design of these units will allow for an easy-storage on any workstation.
•Designed to offer ease in service
Air Entrainment Meters are made out of a cast aluminum that features locking bolts and a palm grip to offer the upper section and test pot with an airtight-seal. There are two balls cocks that come with the machine to fill up with the required water as well as to vent air. The air will be compressed using a hand-pump built into the machine. The connection-valve used for initial pressure as well as the overflow-valve is combined inside the pressure-chamber. These machines feature a connection-valve uses a needle-valve that has a knurled head-screw. Between the test-pot and pressure chamber is the over-flow valve used for pressure-compensation operates using a valve-rocker. On the pressure-chamber is the pressure-valve with a scale that displays the readings that feature a range between 0-100 vol%.
Shrinkage Cone Used For Concrete And Cement
Shrinkage cones are created with the double type of “wall metal vessel” that provides easy cooling and heating that makes use of external types of “liquid temperature control unit.” The laser-beam is used to measure early expansion and shrinkage in building materials, concrete and cement using a one micron-resolution.
The patented-innovation of Shrinkage Cones make it a possibility to measure the expansion and shrinkage of fluid type building materials in the first few minutes or hours after mixing has begun. Expansion of building material has been registered as touch-free as well as extremely exact using the laser beam. There will be no mechanical-coupling that occurs between the sensor and the fluid. To make sure the measured-distance relates with the relative-length change in the material a specimen container is used.
The change in length is then registered using a 1/10 micron resolution, and the values for this measurement are digitized and then stored by software that comes with this system. This software stores the rel. Humidity, temperature and length change.
The Measurement Procedure
•The fluid “building material” is filled into the specimen container that is cone formed
•This container is then positioned underneath the laser-unit mounted on the “high performance” boom stand
•The adjust for the Automatic offset can be completed using a mouse click on the PC
•The autonomous data-logger registers data over several weeks using an “integrated CF-card memory
•The data-logger uses a network-interface, and the data can be readout with just about any software such as Firefox and Internet-Explorer
More information about concrete testing for the construction industry here