CN111999202A - Device and method for rapidly testing water-cement ratio of fresh concrete - Google Patents

Abstract

The invention discloses a device for rapidly testing the water-cement ratio of fresh concrete, which comprises a base, wherein a mass sensor is arranged on the base, a protective cover is arranged outside the base, a heating device is arranged at the top end of the protective cover, a timer is arranged on the surface of the protective cover, and the timer and the mass sensor are both connected with a processor. The device and the method for rapidly testing the water-cement ratio of the fresh concrete can rapidly and accurately test the water-cement ratio of the concrete, and have the advantages of simple testing device, easy operation of the testing method and accurate testing result.

Description

Device and method for rapidly testing water-cement ratio of fresh concrete

Technical Field

The invention relates to a device and a method for rapidly testing the water-cement ratio of fresh concrete, belonging to the field of concrete.

Background

Unmetered water may be added to the concrete, either accidentally or intentionally, throughout the mixing, transporting and placing of the concrete. This results in a larger water cement ratio than the designed water cement ratio, which may reduce the strength of the concrete at a later stage and even cause safety production accidents. For example, after the concrete tanker completes the pour, the drum will be flushed with water. This process can leave a large amount of water in the bottom of the tanker. When the concrete truck returns to the factory for reloading, the water-cement ratio of fresh concrete increases and the performance of the concrete is greatly affected if the above situation is not taken into account.

Therefore, in order to avoid this situation, a method for rapidly and accurately testing the water-cement ratio of concrete is urgently needed.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides the device and the method for quickly testing the water-cement ratio of the fresh concrete, the water-cement ratio of the concrete can be quickly and accurately tested, the testing device is simple, and the testing method is easy to operate.

The technical scheme is as follows: in order to solve the technical problem, the device for rapidly testing the water-cement ratio of the fresh concrete comprises a base, wherein a mass sensor is arranged on the base, a protective cover is arranged outside the base, a heating device is arranged at the top end of the protective cover, a timer is arranged on the surface of the protective cover, and the timer and the mass sensor are both connected with a processor.

Preferably, the heating device is a microwave heating device.

The device and the method for rapidly testing the water-cement ratio of the fresh concrete comprise the following steps:

(1) a piece of fiberglass cloth is prepared, which should have sufficient area to completely wrap the concrete sample. Weighing the total mass M of the glass fiber cloth₁The measurement result should be accurate to 0.1 g;

(2) placing glass fiber cloth in the center of a base, taking 1500 +/-10 g of fresh concrete sample, placing the fresh concrete sample on the glass fiber, and completely wrapping the concrete with the glass fiber cloth;

(3) recording the total mass M of fresh concrete and glass fiber cloth₂；

(4) Starting the heating device, and simultaneously recording the heating time in real time by the processor;

(5) recording the change of the sample quality in the processor, stopping heating when the change of the concrete sample quality is less than 1g within 2min, and recording the final total mass M of the glass fiber cloth and the dry concrete sample₃；

(6) Sample mass M of fresh concrete_cBy the total mass of fresh concrete and glass fibre clothQuantity M₂Minus the total mass M of the glass cloth₁The calculation formula is obtained as follows:

M_c＝M₂-M₁

(7) final dry concrete sample mass M_DBy applying a final mass M₃Minus the total starting mass M₁Determined by the following calculation formula:

M_D＝M₃-M₁

(8) total water content M of freshly mixed concrete samples_wIs the mass of all water evaporated during the drying process in the microwave oven, the mass M of the sample passing through the freshly mixed concrete_cSubtract the final dry concrete sample mass M_DObtained by the following calculation formula:

M_w＝M_C-M_D

(9) total water content M_wIs composed of free water and natural water in aggregate. However, when the aggregate is in a saturated face-dry state, the water-cement ratio in the concrete is determined by the free water. That is, a portion of the mass loss in dry concrete is determined by the loss of natural water in the aggregate. Therefore, the moisture content of the aggregate must be measured to determine the natural water content in the aggregate.

(10) Determining the water content of coarse aggregate and fine aggregate in the raw material of fresh concrete, and weighing the mass M of the tray_Support(ii) a Weighing 1kg +/-10 g of coarse aggregate M_CoarseAnd fine aggregate M_{Thin and thin}Putting the mixture into a tray; putting the tray and the aggregate into a base, starting a microwave heating device, and stopping heating until the mass of the aggregate is less than 1g within 1 min; recording the mass M of the dried aggregate and the tray_Coarse' and M_{Thin and thin}'; moisture content S of coarse aggregate_Coarse＝(M_Coarse’-M_Coarse-M_Support)/M_Coarse(ii) a Water content S of fine aggregate_{Thin and thin}＝(M_{Thin and thin}’-M_{Thin and thin}-M_Support)/M_{Thin and thin}；

(11) Determining the mass of aggregate in the fresh concrete: the removal freedom is calculated according to the mixing proportion of the concrete and the water content of the aggregateThe proportion of the coarse aggregate, the fine aggregate and the cement after being watered to the total of the three is A_Coarse、A_{Thin and thin}、A_Cement(ii) a The mass m of coarse aggregate in the test specimen of the selected concrete_Coarse＝M_D×A_Coarse÷(1-S_Coarse) Test specimen of fine aggregate mass m_{Thin and thin}＝M_D×A_{Thin and thin}÷(1-S_{Thin and thin}) Test of the mass m of cement in the sample_Cement＝M_D×A_Cement；

(12) Quality M of natural water contained in concrete test sample aggregate_{W bone}Can be determined by the following formula:

M_{w bone}＝m_Coarse×S_Coarse+M_{Thin and thin}×S_{Thin and thin}

(13) Content M of free Water in concrete_{Wyou game}Comprises the following steps:

M_{wyou game}＝M_w-M_{w bone}

(14) By the content M of free water in the concrete_{Wyou game}And the cement content m in the sample_CementThe water-cement ratio of the fresh concrete can be determined, and the calculation formula is as follows: W/C ═ M_{Wyou game}/m_Cement。

Has the advantages that: the device for rapidly testing the water-cement ratio of the fresh concrete has the following effects

(1) The test device used in the invention is simple and convenient, and the water-cement ratio of the fresh concrete can be quickly obtained only by measuring the mass change of the concrete and the water content of the aggregate;

(2) the calculation method fully considers the moisture loss of the aggregate, and the test result has high precision.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in figure 1, the device for rapidly testing the water-cement ratio of fresh concrete comprises a base, wherein a mass sensor 3 is arranged on the base, a protective cover 5 is arranged outside the base, a heating device 1 is arranged at the top end of the protective cover 5, the heating device 1 is a microwave heating device 1, a timer 6 is arranged on the surface of the protective cover 5, and the timer 6 and the mass sensor 3 are both connected with a processor 4.

The device and the method for rapidly testing the water-cement ratio of the fresh concrete comprise the following steps:

(1) a piece of fiberglass cloth is prepared, which should be sufficient to completely wrap the concrete sample. Weighing the total mass M of the glass fiber cloth₁The measurement result should be accurate to 0.1 g;

(2) placing glass fiber cloth in the center of a base, taking 1500 +/-10 g of fresh concrete sample, placing the fresh concrete sample on the glass fiber, and completely wrapping the concrete with the glass fiber cloth;

(3) recording the total mass M of fresh concrete and glass fiber cloth₂；

(4) Starting the heating device 1, and simultaneously recording the heating time in real time by the processor 4;

(5) recording the change of the sample quality in the processor 4, stopping heating when the change of the concrete sample quality is less than 1g within 2min, and simultaneously recording the final total mass M of the glass fiber cloth and the dry concrete sample₃；

(6) Sample mass M of fresh concrete_cTotal mass M of fresh concrete and glass fiber cloth₂Minus the total mass M of the glass cloth₁The calculation formula is obtained as follows:

M_c＝M₂-M₁

(7) final dry concrete sample mass M_DBy applying a final mass M₃Minus the total starting mass M₁Determined by the following calculation formula:

M_D＝M₃-M₁

(8) total water content M of freshly mixed concrete samples_wIs the mass of all water evaporated during the drying process in the microwave oven, the mass M of the sample passing through the freshly mixed concrete_cSubtract the final dry concrete sample mass M_DObtained by the following calculation formula:

M_w＝M_C-M_D

(9) total water content M_wIs composed of free water and natural water in aggregate. However, when the aggregate is in a saturated face-dry state, the water-cement ratio in the concrete is determined by the free water. That is, a portion of the mass loss in dry concrete is determined by the loss of natural water in the aggregate. Therefore, the moisture content of the aggregate must be measured to determine the natural water content in the aggregate.

(10) Determining the water content of coarse aggregate and fine aggregate in the raw material of fresh concrete, and weighing the mass M of the tray_Support(ii) a Weighing 1kg +/-10 g of coarse aggregate M_CoarseAnd fine aggregate M_{Thin and thin}Putting the mixture into a tray; putting the tray and the aggregate into a base, starting the microwave heating device 1, and stopping heating until the mass of the aggregate changes less than 1g within 1 min; recording the mass M of the dried aggregate and the tray_Coarse' and M_{Thin and thin}'; moisture content S of coarse aggregate_Coarse＝(M_Coarse’-M_Coarse-M_Support)/M_Coarse(ii) a Water content S of fine aggregate_{Thin and thin}＝(M_{Thin and thin}’-M_{Thin and thin}-M_Support)/M_{Thin and thin}；

(11) Determining the mass of aggregate in the fresh concrete: calculating the proportion of the coarse aggregate, the fine aggregate and the cement after the free water is removed to be A according to the mixing proportion of the concrete and the water content of the aggregate_Coarse、A_{Thin and thin}、A_Cement(ii) a The mass m of coarse aggregate in the test specimen of the selected concrete_Coarse＝M_D×A_Coarse÷(1-S_Coarse) Test specimen of fine aggregate mass m_{Thin and thin}＝M_D×A_{Thin and thin}÷(1-S_{Thin and thin}) Test of the mass m of cement in the sample_Cement＝M_D×A_Cement；

(12) Quality M of natural water contained in concrete test sample aggregate_{W bone}Can be determined by the following formula:

M_{w bone}＝m_Coarse×S_Coarse+M_{Thin and thin}×S_{Thin and thin}

(13) Content M of free Water in concrete_{Wyou game}Comprises the following steps:

M_{wyou game}＝M_w-M_{w bone}

(14) By the content M of free water in the concrete_{Wyou game}And the cement content m in the sample_CementThe water-cement ratio of the fresh concrete can be determined, and the calculation formula is as follows: W/C ═ M_{Wyou game}/m_Cement。

Examples

The formulation of fresh concrete is shown in Table 1, and the design water cement ratio of the concrete is 0.45. By performing the test tests, the following results were obtained:

TABLE 1 concrete mixing ratio

(1) Mass M of glass fiber cloth₁＝128.8g

(2) Total mass M of fresh concrete and glass fiber cloth₂＝1653.0g

(3) Final total mass M of fiberglass cloth and dry-mixed concrete sample 2₃＝1529.7g

(4) Sample mass M of fresh concrete_c＝M₂-M₁＝1524.2g

(5) Final dry concrete sample mass M_D＝M₃-M₁＝1400.9g

(6) Total water content M of freshly mixed concrete samples_w＝M_C-M_D＝123.3g

(7) Moisture content S of coarse aggregate_Coarse1.42%, moisture content of fine aggregate S_{Thin and thin}＝0.64％

(8) The proportions of the coarse aggregate, the fine aggregate and the cement in the concrete after the removal of water were respectively set to the proportions of the total of the coarse aggregate, the fine aggregate and the cement in the concrete shown in Table 1

A_Coarse＝1101×(1-1.42％)/[1101×(1-1.42％)+698×(1-0.64％)+380]＝50.27％

A_{Thin and thin}＝698×(1-0.64％)/[1101×(1-1.42％)+698×(1-0.64％)+380]＝32.13％

A_Cement＝380/[1101×(1-1.42％)+698×(1-0.64％)+380]＝17.60％

(9) In test specimens of selected concrete

Mass m of coarse aggregate_Coarse＝M_D×A_Coarse÷(1-S_Coarse)＝1400.9×50.27％÷(1-1.42％)＝714.38g

Mass m of fine aggregate_{Thin and thin}＝M_D×A_{Thin and thin}÷(1-S_{Thin and thin})＝1400.9×32.13％÷(1-0.64％)＝453.01g

Mass m of cement_Cement＝M_D×A_Cement＝1400.9×17.60％＝453.01g＝246.56g

(10) Concrete test sample aggregate containing natural water quality

M_{w bone}＝m_Coarse×S_Coarse+m_{Thin and thin}×S_{Thin and thin}＝714.38×1.42％+453.01×0.64％＝13.04g

(11) Content M of free Water in concrete_{Wyou game}＝M_w-M_{w bone}＝123.30-13.04＝110.26g

(12) Water-cement ratio W/C of fresh concrete M_{Wyou game}/m_Cement＝110.26/246.56＝0.447

(13) The water-cement ratio W/C of the fresh concrete obtained by the test is 0.447, and the error is only 0.67 percent compared with the designed water-cement ratio of 0.45. It can be seen that the method is highly accurate.

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims (3)

1. The utility model provides a device of quick test fresh concrete water-cement ratio which characterized in that: the automatic cleaning device comprises a base, install the quality sensor base on the base and install the protection casing outward, install heating device on the protection casing top, have the time-recorder at protection casing surface mounting, the time-recorder all is connected with the treater with quality sensor.

2. The device for rapidly testing the water-cement ratio of fresh concrete according to claim 1, characterized in that: the heating device is a microwave heating device.

3. An apparatus and method for rapidly testing the water-cement ratio of fresh concrete by using the apparatus and method as claimed in claim 1 or 2, characterized by comprising the following steps:

(1) preparing a piece of glass fiber cloth with enough area to completely wrap the concrete sample, and weighing the total mass M of the glass fiber cloth₁；

(2) Placing glass fiber cloth in the center of a base, taking 1500 +/-10 g of fresh concrete sample, placing the fresh concrete sample on the glass fiber, and completely wrapping the concrete with the glass fiber cloth;

(3) recording the total mass M of fresh concrete and glass fiber cloth₂；

(4) Starting the heating device, and simultaneously recording the heating time in real time by the processor;

(5) recording the change of the sample quality in the processor, stopping heating when the change of the concrete sample quality is less than 1g within 2min, and recording the final total mass M of the glass fiber cloth and the dry concrete sample₃；

(6) Sample mass M of fresh concrete_cTotal mass M of fresh concrete and glass fiber cloth₂Minus the total mass M of the glass cloth₁The calculation formula is obtained as follows:

M_c＝M₂-M₁

(7) final dry concrete sample mass M_DBy applying a final mass M₃Minus the total starting mass M₁Determined by the following calculation formula:

M_D＝M₃-M₁

(8) total water content M of freshly mixed concrete samples_wIs the mass of all water evaporated during the drying process in the microwave oven, the mass M of the sample passing through the freshly mixed concrete_cSubtract the final dry concrete sample mass M_DObtained by the following calculation formula:

M_w＝M_C-M_D

(9) determining the water content of coarse aggregate and fine aggregate in the raw material of fresh concrete, and weighing the mass M of the tray_Support(ii) a Weighing 1kg +/-10 g of coarse aggregate M_CoarseAnd fine aggregate M_{Thin and thin}Putting the mixture into a tray; putting the tray and the aggregate into a base, starting a microwave heating device, and stopping heating until the mass of the aggregate is less than 1g within 1 min; recording the mass M of the dried aggregate and the tray_Coarse' and M_{Thin and thin}'; moisture content S of coarse aggregate_Coarse＝(M_Coarse’-M_Coarse-M_Support)/M_Coarse(ii) a Water content S of fine aggregate_{Thin and thin}＝(M_{Thin and thin}’-M_{Thin and thin}-M_Support)/M_{Thin and thin}；

(10) Determining the mass of aggregate in the fresh concrete: calculating the proportion of the coarse aggregate, the fine aggregate and the cement after the free water is removed to be A according to the mixing proportion of the concrete and the water content of the aggregate_Coarse、A_{Thin and thin}、A_Cement(ii) a The mass m of coarse aggregate in the test specimen of the selected concrete_Coarse＝M_D×A_Coarse÷(1-S_Coarse) Test specimen of fine aggregate mass m_{Thin and thin}＝M_D×A_{Thin and thin}÷(1-S_{Thin and thin}) Test of the mass m of cement in the sample_Cement＝M_D×A_Cement；

(11) Quality M of natural water contained in concrete test sample aggregate_{W bone}Can be determined by the following formula:

M_{w bone}＝m_Coarse×S_Coarse+M_{Thin and thin}×S_{Thin and thin}

(12) Content M of free Water in concrete_{Wyou game}Comprises the following steps:

M_{wyou game}＝M_w-M_{w bone}

(13) By the content M of free water in the concrete_{Wyou game}And the cement content m in the sample_CementThe water-cement ratio W/C of the fresh concrete can be determined, and the calculation formula is as follows: W/C ═ M_{Wyou game}/m_Cement。

Images