The strength of concrete is generally estimated after 28 days by crushing field test cubes or cylinders made from the representative concrete used for the structure. The utility of ascertaining strength after 28 days is often questioned since by this time considerable concrete would have been placed and work may have progressed. It is then rather too late for remedial measures. It is therefore of tremendous advantage to predict 28 days strength within a few hours of casting the concrete so that, we have a good idea about the strength of the concrete.
The rate of gain of strength of concrete depends on the reaction rate of cement and additions with water (Hydration). In common with all chemical reactions, the rate of reaction depends on reaction of temp. Higher reaction temperature gives higher rate of reaction e.g. the concrete gains strength more rapidly when its temp. is higher. Accelerated curing is the process by which the temperature of the concrete is raised artificially by applying external heat to speed up the rate of gain in strength.
The test method covers procedures for curing test specimens of concrete stored under conditions intended to accelerate the development of strength. The procedures are: Procedure A- Warm Water Method, Procedure B-Boiling Water Method
General Description & Specification:
Accelerated Curing Tank having capacity to accommodate 6/12/18 Concrete Cubes of 150mm size with a facility for accelerated curing by Boiling water method up to temperature range : 100 +/- 2 deg.C as per IS standard IS : 9013. Also it will have capacity for curing by warm water method at temperature 55 +/- 2 deg.C
Tank will consist of a rectangular double walled metal cabinet, inside lined with stainless steel, outer powder coated. Easily replaceable high Wattage heaters are mounted in side the chamber. A slow speed stirrer is provided to circulate water inside the chamber to maintain the uniform temperature of water. A strong stainless steel perforated platform is provided for keeping the cubes and also have a lid with lifting handle to cover the chamber.
The temperature is indicated and controlled by a DIGITAL auto tuning PID Temp. Controller with soak timer to control the duration of heating and then to shut down the system without manual attendance. The front panel will have power supply indicating lamp, control action indication lamp and one main switch. Suitable for operation on 220 V, 50 Hz single phase, AC supply or 440 V 50 Hz, three phase AC supply, for bigger size of curing tank.
Rubber hand Gloves. Spare Heaters. Low water Level cut off device to safeguard heaters against low water level burn out In built refrigeration system for curing at 27 deg C
Recommended Accessories & Consumbles
The following accessories and consumables are not part of the standard supply and are mandatory for the testing work
Accelerated Curing Autoclave : By Steam Pressure
Accelerated Curing Drier : By Dry Heat