A rapid evaluation method for horizontal segregation resistance of self-compacting concrete

Abstract

This invention proposes a rapid evaluation method for the horizontal segregation resistance of self-compacting concrete, including measuring the penetration depth of the concrete. P d The variance of the mass of coarse aggregate in concrete at different horizontal positions after stabilization. R h ,Record P d and R h The correspondence is obtained to satisfy the preset conditions. P d This invention evaluates the horizontal segregation resistance of concrete by recording the penetration depth of self-compacted concrete in the horizontal direction. P d and quality variance R h The relationship allows for the measurement of only the penetration depth. P d It can determine the horizontal segregation resistance of concrete; the measurement is simple and efficient; the diameter and spacing of the reinforcing bars can be adjusted to measure the performance of concrete with different coarse aggregate particle sizes and different water-cement ratios.

Description

Technical Field

[0001] This invention belongs to the technical field of testing or analyzing materials by measuring their chemical or physical properties, and specifically relates to a rapid evaluation method for the horizontal segregation resistance of self-compacting concrete. Background Technology

[0002] Concrete segregation is a phenomenon where the cohesion between the components of a concrete mix is ​​insufficient to resist the settling of coarse aggregates, leading to the separation of concrete components and resulting in uneven internal composition and structure. It typically manifests as the separation of coarse aggregates from the mortar. Concrete segregation affects the pumpability of concrete, reduces economic efficiency, impacts the appearance of the concrete structure, significantly decreases concrete strength, seriously compromises safety, and greatly reduces the concrete's impermeability, frost resistance, and other durability properties.

[0003] Considering the hazards of concrete segregation, segregation resistance plays an important role in the load-bearing performance of self-compacting concrete, because poor segregation resistance will lead to poor concrete deformation capacity, blockage around the reinforcing bars, high drying shrinkage rate, and uneven compressive strength.

[0004] Therefore, the measurement and evaluation of the segregation resistance of self-compacting concrete is crucial. However, the measurement and evaluation of the segregation resistance of self-compacting concrete should also distinguish its direction. Due to the special physical properties of concrete, it is even more difficult to measure its segregation resistance in the horizontal direction. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects in the prior art and to provide a rapid evaluation method for the horizontal segregation resistance of self-compacting concrete.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution: a rapid evaluation method for the horizontal segregation resistance of self-compacting concrete, the method comprising measuring the penetration depth P of the concrete. d The variance R of the mass of coarse aggregate in concrete at different positions in the horizontal direction after the measurement stabilizes. h Record P d and R h The correspondence is obtained to obtain P that satisfies the preset conditions. d The scope is used to evaluate the horizontal segregation resistance of concrete.

[0007] Preferably, the penetration depth P of the concrete is measured. d Includes the following steps:

[0008] S1.1 Close the mold's through component, pour concrete into the mold's inlet without consolidation, and set the top of the poured concrete horizontally;

[0009] S1.2 After a preset time t1, the initial height of the concrete is obtained by a measuring mechanism;

[0010] After a preset time t2 in step S1.3, select several measuring points within the mold and use a measuring mechanism to obtain the current height of the concrete. Calculate the average height of the vertical rod's descent, and record this as the penetration depth P. d .

[0011] Preferably, after the concrete passes through the component in the mold and flows a certain distance in the horizontal direction, the variance R of the mass of the coarse aggregate in the concrete at different positions in the horizontal direction is measured. h .

[0012] Preferably, measuring the variance of the mass of coarse aggregate in concrete at different locations in the horizontal direction includes the following steps:

[0013] The concrete in the S2.1 mold has stopped flowing;

[0014] S2.2 The concrete that passes through the component is placed into several first molds based on different positions in the horizontal direction, and the concrete that does not pass through the component is placed into second molds;

[0015] S2.3 Clean the concrete in the first and second molds respectively, retain the coarse aggregate, dry and weigh it;

[0016] S2.4 Calculate the variance R of aggregate quality for the two groups. h .

[0017] Preferably, the first mold and the second mold are identical.

[0018] Preferably, the concrete passing through the component is divided into N equal parts in the horizontal direction, and concrete of the same volume is cut off. The coarse aggregate in each part is separated, dried, and weighed.

[0019] Preferably, N is 6.

[0020] Preferably, the average mass of aggregates in the mix proportion and the variance R of the mass of the two groups of aggregates are calculated. h If the value is less than the preset value, the horizontal anti-segregation performance of the concrete meets the requirements; otherwise, the horizontal anti-segregation performance does not meet the requirements.

[0021] Preferably, the preset value is 10%.

[0022] Preferably, record P d and R h The correspondence is obtained by satisfying R. h less than 10% of the required penetration depth P d As the best P d scope.

[0023] This invention proposes a rapid evaluation method for the horizontal segregation resistance of self-compacting concrete, including measuring the penetration depth P of the concrete. d The variance R of the mass of coarse aggregate in concrete at different positions in the horizontal direction after the measurement stabilizes. h Record P d and R h The correspondence is obtained to obtain P that satisfies the preset conditions. d The scope is used to evaluate the horizontal segregation resistance of concrete.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) By recording the penetration depth P of self-compacting concrete in the horizontal direction d and quality variance R h The relationship allows for the measurement of only the penetration depth P. d This allows for the determination of the horizontal segregation resistance of concrete;

[0026] (2) Measurement is simple and efficient;

[0027] (3) The diameter and spacing of the reinforcing bars can be adjusted to measure the performance of concrete with different coarse aggregate particle sizes and different water-cement ratios. Attached Figure Description

[0028] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0030] This invention relates to a rapid evaluation method for the horizontal segregation resistance of self-compacting concrete, the method comprising measuring the penetration depth P of the concrete. d The variance R of the mass of coarse aggregate in concrete at different positions in the horizontal direction after the measurement stabilizes. h Record P d and R h The correspondence is obtained to obtain P that satisfies the preset conditions. d The scope is used to evaluate the horizontal segregation resistance of concrete.

[0031] Measuring the penetration depth P of concrete d Includes the following steps:

[0032] S1.1 Close the mold's through component, pour concrete into the mold's inlet without consolidation, and set the top of the poured concrete horizontally;

[0033] S1.2 After a preset time t1, the initial height of the concrete is obtained by a measuring mechanism;

[0034] After a preset time t2 in step S1.3, select several measuring points within the mold and use a measuring mechanism to obtain the current height of the concrete. Calculate the average height of the vertical rod's descent, and record this as the penetration depth P. d .

[0035] In this embodiment, after 2 minutes, the permeameter is lowered into the concrete. After 45 seconds, the descent value is observed. Generally, three measurement points are selected within the mold, and the average descent value of the vertical rod is calculated and recorded as the penetration depth P. d The settings of t1 and t2 here are confirmed by technicians based on the actual situation, so that the concrete can flow freely to a stable state and the vertical rod has enough time to fall freely.

[0036] After the concrete passes through the component in the mold and flows a certain distance horizontally, the mass variance R of the coarse aggregate in the concrete at different positions in the horizontal direction is measured. h .

[0037] Measuring the variance of concrete coarse aggregate mass at different locations in the horizontal direction includes the following steps:

[0038] The concrete in the S2.1 mold has stopped flowing;

[0039] S2.2 The concrete that passes through the component is placed into several first molds based on different positions in the horizontal direction, and the concrete that does not pass through the component is placed into second molds;

[0040] The first mold and the second mold are identical.

[0041] The concrete passing through the component is divided into N equal parts in the horizontal direction. The same volume of concrete is cut off, and the coarse aggregate in each part is separated, dried, and weighed; N is 6.

[0042] S2.3 Clean the concrete in the first and second molds respectively, retain the coarse aggregate, dry and weigh it;

[0043] S2.4 Calculate the variance R of aggregate quality for the two groups. h .

[0044] Calculate the average aggregate mass and the variance R of the aggregate mass of the two groups in the mix proportion. h If the value is less than the preset value, the horizontal anti-segregation performance of the concrete meets the requirements; otherwise, the horizontal anti-segregation performance does not meet the requirements.

[0045] The default value is 10%.

[0046] Record P d and R h The correspondence is obtained by satisfying R. h less than 10% of the required penetration depth P d As the best P d scope.

[0047] In this embodiment, the penetration depth P of the concrete can be measured. d The method is used to evaluate the horizontal segregation resistance of concrete.

[0048] This embodiment is merely an illustration of the present invention and is not intended to limit the present invention. For those skilled in the art, any related improvements should also be considered within the scope of protection of the present invention.

Claims

1. A rapid evaluation method for the horizontal segregation resistance of self-compacting concrete, characterized in that: The method includes measuring the penetration depth P of the concrete. d The variance R of the mass of coarse aggregate in concrete at different positions in the horizontal direction after the measurement stabilizes. h ; Measuring the penetration depth P of concrete d Includes the following steps: S1.1 Close the mold's through component, pour concrete into the mold's inlet without consolidation, and set the top of the poured concrete horizontally; S1.2 After a preset time t1, the initial height of the concrete is obtained by a measuring mechanism; After a preset time t2 in step S1.3, select several measuring points within the mold and use a measuring mechanism to obtain the current height of the concrete. Calculate the average height of the vertical rod's descent, and record this as the penetration depth P. d ; After concrete passes through the component in the mold and flows a certain distance horizontally, the concrete that has passed through the component is divided into N equal parts horizontally. Equal volumes of concrete are cut off, and the variance R of the coarse aggregate mass of the concrete at different positions in the horizontal direction is measured. h This includes the following steps: The concrete in the S2.1 mold has stopped flowing; S2.2 Concrete that passes through the component is placed into several first molds at different positions in the horizontal direction, and concrete that does not pass through the component is placed into second molds; the first molds and the second molds are identical; S2.3 Clean the concrete in the first and second molds respectively, retain the coarse aggregate, dry and weigh it; S2.4 Calculate the variance R of aggregate quality for the two groups. h ; Calculate the average aggregate mass and the variance R of the aggregate mass of the two groups in the mix proportion. h If the value is less than the preset value, the horizontal anti-segregation performance of the concrete meets the requirements; otherwise, the horizontal anti-segregation performance does not meet the requirements. Record P d and R h The correspondence is obtained by satisfying R. h less than 10% of the required penetration depth P d As the best P d The scope is used to evaluate the horizontal segregation resistance of concrete.

2. The method for rapid evaluation of the horizontal segregation resistance of self-compacting concrete according to claim 1, characterized in that: The coarse aggregate in each section is separated, dried, and weighed.

3. The method for rapid evaluation of the horizontal segregation resistance of self-compacting concrete according to claim 1, characterized in that: N is 6.

4. The method for rapid evaluation of the horizontal segregation resistance of self-compacting concrete according to claim 1, characterized in that: The default value is 10%.

Images