Alkali-Silica-Reactivity Unit

Alkali-Silica-Reactivity (ASR) is the process in which certain minerals (mostly Glass type silica) in the presence of moisture are broken down by the highly alkaline environment of concrete producing a gel that expands creating tensile forces in the concrete matrix which cause cracking of the concrete. The concrete then allows more water to infiltrate into the concrete creating more gel, more expansion etc.  Ultimately the concrete fails or disintegrates.

Typically indicators of ASR are random map cracking and, in advanced cases, closed joints and attendance spalled concrete. Cracking due to ASR usually appears in the areas with a frequent supply of moisture, such as close to the waterline in piers, near the ground behind retaining walls, near joints and free edges in pavements, or in piers or columns subject to wicking action. Petrographic examination can conclusively identify ASR.

• Inside 100% stainless steel against corrosion
• Bath inside inert gas welded
• Perfect insulation to ensure that the temperature outside is not over 30^oC
• Free user programmable temperature curves from room temperature up to 80^oC
• Temperature deviation below 0.5K
• Two stainless steel temperature sensors inside up to 4 extra sensors may be connected
• Fulfilling all RILEM and national standards
• Graphical colour display showing all temperature over time
• CF card inside for registration all temperatures over time
• Network and Internet connection for checking all parameters and temperatures remotely
• Two 6kW heating units with backup functionality (machine can run also with one unit)
• Triple overheating protection: mechanical switch, electronically and by software
• Contact-less and so wear less switching of the heating unit additional interrupter, if the electronic switch will fail
• Ground fault circuit interrupter for maximum electrical safety
• as option a fog generating, realising nearly 100% humidity even at room temperature

• Inner size (L x W x H) 280 x 130 x 400 cm
• Made of 2mm stainless steel, complete welded, pickled and passivated
• Lid with drop-down tin. Removable grating for concrete specimen at 50mm level, mesh opening 20 x 20 mm.
• Specimen spaces at 260mm height.
• Two handhold’s at the length sides

• For temperature below 40^oC we recommend the additionally power fog system which makes extreme fine fog and nearly 100% rel. humidity also at low water temperatures. With a high pressure pump and special stainless steel nozzles. The size of the droplets is smaller than 30 micron. The fog function may be controlled with the ACR control unit by duration and intensity. Fog power about 1.2 l/hour. Water quality W10 required.

• for measuring the length change of the specimen 280 x 75 x 75mm or cylinders 300 x 150mm. There is a socket in the base plate for fixing a 10mm ball. Including a digital probe. Resolution 0.5 micron, accuracy 2.6 micron. Including a carbon made reference bar 280mm (or 300mm)

• 14mm hexagon bolt central hole M5 (5mm) with countersink 9mm x 45^o, stainless steel 1.4305

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