Haridarshan Instru-Lab

Sarkhej, Ahmedabad, Gujarat

This test is used to determine the elapsed time between batching of a concrete sample and when it is deemed by standard methods to have set. The method involves measuring the penetration resistance of a test sample, which has had coarse particles removed at periodic intervals. It is particularly useful, in determining the effect on setting time of admixtures in the concrete, where these may have been introduced specifically to increase the setting time.
It consists of cylindrical spring housing with a plunger attached to the top of the spring. Penetration needle is attached to the other end of the spring housing. The plunger is graduated in 1 kg divisions, to a maximum capacity of 60kg, which can be read with respect to the top end of the spring housing. A set of six needle points with areas of 645, 323, 161, 65, 32 and 16mm2 are provided. Supplied complete in a wooden carrying case.

Pocket Penetrometer

Consists of a needle having face area 3/10 sq.cm. and graduated at a distance of 25mm. The needles point is an integral part of barrel which houses a calibrated spring. The spring is confined in a sleeve. The resistance offered by the concrete mortar is shown on the direct reading scale with a marker ring which holds its position when released. Scale range is 0-50 kg/cm2 when the penetration resistance reaches a value of 35kg/cm2 the concrete is assumed initially set. Supplied complete in a leather carrying case. AS PER ASTM C-403

The unit consists of two movable frames pivoted at one end. The lateral extensometer is fixed to the specimen with the help of tightening screws. The lateral extension is indicated on a dial gauge of 0.002 mm x 12 mm travel. The extension is magnified 2.5 times and the dial gauge readings are to be divided by 2.5 to get the exact readings. A spacer strip is provided to initially set the dial gauge and can be removed after initial setting. Supplied in a wooden carrying case.

The unit consists of two movable frames pivoted at one end. The lateral extensometer is fixed to the specimen with the help of tightening screws. The lateral extension is indicated on a dial gauge of 0.002 mm x 12 mm travel. The extension is magnified 2.5 times and the dial gauge readings are to be divided by 2.5 to get the exact readings. A spacer strip is provided to initially set the dial gauge and can be removed after initial setting. Supplied in a wooden carrying case.

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 descripation & specifications

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.

optional accessories

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