SU1293652A1 - Method of determining concrete strength in design age and cement activity - Google Patents

Abstract

This invention relates to methods for controlling the production of cement and concrete and reinforced concrete products. The goal is to increase control accuracy. During the steaming of the samples, the change in the electrosurface mass transfer potential is measured. Compressive strength is determined at specified times, determined by the change in potential. Strength at design age and activity are determined by the formulas. (L with

Description

The invention relates to methods for monitoring the availability and compliance with the specified parameters of materials and products in their manufacture and can be used in the production of cement, concrete and reinforced concrete products.

The purpose of the invention is to increase accuracy.

The method is carried out as follows.

A concrete mix of a given composition is prepared and 6 cubic samples measuring 15,515 cm in size are made from it (2 identical batches of 3 samples each). In one of the molded samples, the sensor is installed in the form of two stainless steel electrodes, partially covered (5-10% of the surface) of tin by lead soldering and having an area of 1 to 2 cm. The electrodes are mounted in the same plane, perpendicular to the open surface of the mold, at a distance of 2 cm from each other.

Both electrodes are connected to a high input resistance millivolmeter. In parallel, the sensors are connected to a shunt-resistance of 1-8 kΩ.

After a two-hour exposure, the samples are steamed in a laboratory chamber with a temperature rise over J h and isothermal heating at 80-85 C.

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the camera for a period of time until the maximum of the electrosurface potential disappears. This time is determined and tested for compression by the first series of samples, the second series of samples is maintained under normal conditions and tested for compression one day after the peak-like change of the electrical surface potential. The concrete strength at design age is determined by the formula.

With the accelerated determination of the activity of cement, the same number of squirrel-sized samples are made from cement mortar. See the paring and testing as for concrete samples.

Claims (1)

Invention Formula A method for determining the strength of concrete at the design age and cement activity, including the manufacture of beta- and mortar samples, steaming them and testing for strength, characterized in that, in order to improve accuracy, the change in the electro-surface potential of mass-energy transfer in the samples during by steaming them, from the curve obtained, the time from the start of the steaming to 1 is determined: the change in the peak and maximum of the electro-surface potential and the cooling time thirty The change in the electrosurface is measured to 35 until the maximum of the electrosurface potential disappears, the compressive strength is determined at the moment when the maximum of the electrosurface potential disappears and a day after whom massoenergopotential in samples when steaming. AT the steaming process measures the time from start steaming to peak changes and maximum of the electric-tope-peak change of the electric-potential potential. Parking lead surface potential, and strength until the occurrence of a maximum of electrosurface-concrete at the project age and activity potential. Then the cement is cooled, determined by the formulas Igtne H., R, (HH,) ig.b - :. j, 2 ± 827 t. 18 "And (in, -".), -; 1  - compressive strength of concrete at the project age, Sha; PJ is the compressive strength at the moment when the maximum of the electrosurface potential disappears. MPa; the camera for a period of time until the maximum of the electrosurface potential disappears. This time is determined and tested for compression by the first series of samples, the second series of samples is maintained under normal conditions and tested for compression one day after the peak-like change of the electrical surface potential. The concrete strength at design age is determined by the formula. With the accelerated determination of the activity of cement, the same number of squirrel-sized samples are made from cement mortar. See the paring and testing as for concrete samples. Invention Formula A method for determining the strength of concrete at design age and cement activity, including the manufacture of concrete and mortar samples, steaming them and testing for strength, characterized in that, in order to improve accuracy, the change in the electrical surface energy of mass transfer is measured in samples steaming, from the curve obtained, determine the time from the beginning of the steaming to 1: the step change and maximum of the electrosurface potential and the cooling time surface potential, compressive strength is determined at the time of the disappearance of the maximum electrosurface potential and a day after Ig (tai3 x-t) - | ig-u; r J ..lln) 2,827 R is the compressive strength one day after the peak-like change in the electrosurface potential, MPa;  cv - project age, h; 31293652 G is the time from the peak-like effect due to the surface potentiation of the electrosurface, h; rn is the time from the beginning of the steaming — the time from the beginning of the steaming-5 to the peak-like change to the maximum of the electro-surface-to-surface potential, h; la, h; tof - cooling time - to disappeared-K, - cement activity, MPa, a new maximum of the electro-2,827 lg672 lg (t (28 days,).