CN104749349A - Novel detachable L-shaped box - Google Patents

Abstract

The invention discloses a detachable novel L-shaped box, which comprises a vertical box body and a horizontal box body, the vertical box body and the horizontal box body are connected with a detachable horizontal groove, the vertical box body, the horizontal box body The sides of the body and the horizontal tank are respectively provided with scales, the height of the vertical box is 0.5m-1m, the width is 0.2m-0.5m, and the thickness is 0.15m-0.3m; the horizontal box and the horizontal tank The total length is 1.2m-2.5m, the width is 0.2m-0.5m, and the height is 0.1m-0.3m; a bent frame is movably connected above the horizontal groove, and the bent frame is provided with at least 2 connection holes, which are connected Steel bars extending to the bottom of the horizontal slot are arranged in the hole, and movable doors connected by sliding door slots are also arranged at the connection between the horizontal box body and the horizontal slot and at the end of the horizontal slot. The invention can quantify key evaluation indexes, comprehensively and accurately evaluate the working performance of fluid concrete, is easy to popularize and apply in practice, and has the advantages of wide adaptability, easy operation, high accuracy, cost saving and the like.

Description

A new detachable L-shaped box

technical field

The invention relates to the field of construction engineering, and more specifically relates to a new detachable L-shaped box for evaluating the working performance of concrete.

Background technique

In recent years, high-fluidity concrete represented by high-performance concrete and pumped concrete has been widely used in engineering. Weber consistency and slump are important indicators to reflect the working performance of dry hard concrete and ordinary concrete respectively, but they are not suitable for high fluidity concrete. The reason is that, compared with traditional plastic concrete, high-fluidity concrete has a great difference in the types and proportions of raw materials. Generally, the amount of cementitious material used in high-fluidity concrete is relatively large. In addition to cement, it is often mixed with more ultra-fine powder mineral admixtures, the water-cement ratio is relatively low, and the sand ratio is relatively large. Under the condition of lower water-binder ratio and less water consumption, greater fluidity can be obtained by using superplasticizer. Due to the characteristics of these raw materials and proportioning, the slump value of high-fluidity concrete is usually greater than 180mm, and the fluidity is very high, but the viscosity of the mixture is relatively high, and the deformation speed is slow. So far, the quantitative measurement of the working performance of concrete mixtures still adopts the relatively mature slump index, but the slump can only reflect the final deformation of the mixture, but it is difficult to reflect its deformation speed, and the deformation speed reflects the final deformation of the mixture. The rheological characteristics such as the viscosity of the mixture and the adhesion to the pipe wall are closely related to the pumping performance of the concrete. Therefore, for concrete with low water-binder ratio and high fluidity, it is very important to evaluate the deformation speed of the mixture quantitatively while reflecting the deformation capacity.

In addition to fluidity, the working performance of concrete also includes stability and passability. In order to accurately evaluate the working performance of concrete and carry out construction quality control, some scholars and researchers have proposed a variety of new measurement methods and designed some new special instruments. For example, L-type flow meter method, box flow method, Orimet test method, O-type and V-type funnel flow method, etc. Japanese scholars Murata and Suzuki proposed the inclined tube flow method to measure the fluidity of mortar. Homma et al. Considering the rheology, a J-type flow device is proposed to measure the shear stress and shear rate of concrete. These measurement methods reflect the working performance of concrete from different angles, but they are not perfect in terms of the production of test equipment, the ease of operation of the test, the accuracy of control, evaluation methods and standards, and the amount of concrete, and some instruments are expensive. To be used by specially trained personnel, not universal.

The L-shaped box is currently the most widely used concrete work performance test device. Its structure is simple, easy to operate, and can be used to evaluate the fluidity and passing capacity of concrete by recording the concrete height and observing with naked eyes. However, due to the complex working behavior of concrete, the existing L-shaped box test can only make a qualitative evaluation of some indicators of concrete (such as passing ability), and the test results lack wide adaptability. For example, the evaluation of passing ability can only Whether it meets the engineering requirements is given, but it is obviously difficult to meet the requirements for qualitative evaluation due to the influence of the distribution density of steel bars, steel bar diameter, and surface roundness in the project. On the other hand, the L-box is not convincing in evaluating the performance of self-compacting concrete. Due to the high sand rate and high fluidity of self-compacting concrete, it can meet the requirements of the passing performance index of the L-shaped box under the conventional mix ratio design, but obviously there are differences in its engineering performance. Due to the limitations of the L-shaped box, it is not included in the current code as a means of evaluating the performance of concrete.

Generally speaking, the existing L-shaped box has certain advantages in evaluating the performance of concrete engineering because of its simple structure and easy operation. However, to make it more adaptable and the results more reliable and scientific, major improvements are still needed At present, the laboratory methods used to evaluate the working performance of high-performance concrete and pumped concrete at home and abroad are mainly slump expansion test and J-ring test, which are improved and expanded on the basis of slump, supplemented by the current The L-shaped box test can only qualitatively analyze the working performance of a certain aspect of fluid concrete, and cannot quantify its evaluation results. At the same time, its adaptability is limited, and it is difficult to standardize and apply in practice. At the same time, the existing L-shaped box test The box cannot be disassembled and combined at will, which causes a lot of inconvenience in the test.

Contents of the invention

The purpose of the present invention is to provide a new detachable L-shaped box in order to overcome the deficiencies in the prior art. The present invention can monitor the flow process of fluid concrete under different reinforcement distributions, and propose a new test based on this method, supplemented by image capture and analysis technology, to quantify key evaluation indicators, comprehensively and accurately evaluate the working performance of fluid concrete, easy to popularize and apply in practice, and has wide adaptability, easy operation, high accuracy and cost saving Etc.

The purpose of the present invention is achieved through the following technical solutions:

A new detachable L-shaped box, including a vertical box and a horizontal box, the vertical and horizontal boxes are connected with a detachable horizontal slot, and the vertical box, the horizontal box and the horizontal slot Scales are respectively provided on the side of the vertical box, the height of the vertical box is 0.5m-1m, the width is 0.2m-0.5m, and the thickness is 0.15m-0.3m; the total length of the horizontal box and the horizontal tank is 1.2m -2.5m, the width is 0.2m-0.5m, and the height is 0.1m-0.3m; a bent frame is movably connected above the horizontal groove, and the bent frame is provided with at least 2 connection holes, and the connection holes are provided with The steel bar extending to the bottom of the horizontal tank, the connection between the horizontal box body and the horizontal tank and the end of the horizontal tank are also provided with movable doors connected by sliding door slots.

Both sides of the bent frame are provided with card slots for engaging the bent frame with the horizontal groove.

Described vertical box body, horizontal box body, horizontal groove and bent shelf are all made of plexiglass.

The horizontal trough is provided with a detachable extension.

The length of the horizontal box is 0.1m-0.3m.

The width of the bent frame is 0.015m-0.05m, and the thickness is 0.03m-0.04m.

The depth of the clamping groove is at least 0.02m.

The steel bars are one or more of ribbed, smooth round or welded stirrups.

The movable door is higher than the horizontal box body and the horizontal slot.

Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

1. vertical box body of the present invention, horizontal box body and horizontal tank side are all provided with scale, and all are made of organic glass, can be by observing concrete flow process, record its liquid level (fluid surface angle) and flow velocity at different moments Changes, and then determine the key rheological parameters of fluid concrete, such as yield stress and plastic viscosity;

2. the top of the horizontal trough of the present invention is provided with a reinforcing bar stretching to the bottom of the horizontal trough through a bent frame, so that the simulation effect reaches the best, through which the variation of the percentage of concrete that passes through the coarse aggregate of the reinforcing bar under different reinforcing bar distributions can be tested, Quantitatively determine the passing capacity of high-fluidity concrete under different steel bar densities, and evaluate its pouring performance, which has wide adaptability.

3. The specifications and dimensions of the vertical box, the horizontal box and the horizontal tank in the present invention are obtained through strict design calculations and conclusions, which not only take into account the reliability and simplicity of the test, but also eliminate the influence of boundary effects, and the test accuracy high.

4. The horizontal box and the horizontal tank in the present invention can be disassembled and combined, and a dodge door is also provided to control the flow and discharge of concrete. The overall structure is simple, easy to operate, and cost-saving.

Description of drawings

Fig. 1 is a schematic diagram of the three-dimensional structure of the present invention.

Figure 2 is a schematic side view of the bent frame and steel bars.

Fig. 3 is a top view structural schematic diagram of the bent shelf.

Fig. 4 is the fluid surface angle at a certain moment measured by the present invention.

Figure 5 shows the passing rate of coarse aggregate under different reinforcement distributions.

Reference signs: 1-Vertical box 2-Horizontal box 3-Horizontal groove 4-Bent frame 5-Rebar 6-Dodge door 7-Travel door 8-Card slot 9-Connection hole

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figures 1 to 3, a new type of detachable L-shaped box, including a vertical box 1 and a horizontal box 2 connected as one, the end of the horizontal box 2 is movably connected with the horizontal groove 3, vertical Box 1, horizontal box 2 and horizontal tank 3 are all made of plexiglass with a thickness of 0.5-1.5cm, and their sides are marked with scales, which is convenient for tracking the liquid level changes during the entire flow of concrete. Specifically, Set a grid every 5cm as the main scale mark, and set a sub-scale mark every 1cm; in order to ensure sufficient potential energy for the generation of concrete flow and take into account the convenience of the test, the height of the vertical box 1 is 0.5m-1m, In order to eliminate the boundary effect, the width is set to 0.2m-0.5m, and the thickness is set to 0.15m-0.3m; in order to obtain the concrete flow velocity and the liquid level variation in the process of completing the flow, the total length of the horizontal box 2 and the horizontal tank 3 is 1.2m-2.5m, width 0.2m-0.5m, height 0.1m-0.3m, in which the length of the horizontal box 2 is set to 0.1m-0.3m; the horizontal tank 3 is provided with a detachable extension section, the extension section The length is 0.5m-1.2m. If only the passing capacity of the concrete is tested, the extension of the horizontal groove 3 can be removed.

A plurality of bent shelves 4 can be freely arranged above the horizontal groove 3, and the bent shelves 4 are also made of plexiglass, with a width of 0.015m-0.05m and a thickness of 0.03m-0.04m. Groove 8, card slot 8 is used to clamp the bent frame 4 and the two side plates of the horizontal slot 3 together, in order to ensure the fixing effect, the depth of the card slot 8 is not less than 0.02m; there are at least two Connecting hole 9, be set to 3 connecting holes 9 in the present embodiment, be connected with the steel bar 5 that stretches to the bottom of horizontal groove 3 in the connecting hole 9, reinforcing bar 5 can select ribbed, light circle form for use, also can add welding stirrup; Since the bent frame 4 can be freely moved, assembled and disassembled on the horizontal groove 3, it can accurately simulate the number and row spacing of different steel bars 5, the number of different steel bars 5, and the flow and passing capacity of fluid concrete under the condition of stirrups.

The present invention is also provided with two dodge doors, the dodge door 6 is arranged at the junction of the horizontal box body 2 and the horizontal tank 3 for controlling the flow of concrete, and the other dodge door 7 is arranged at the end of the horizontal tank 3 for removing Concrete after the completion of the test, dodge doors 6,7 are all higher than horizontal casing 2 and horizontal groove 3, and horizontal groove 3 is also respectively provided with the sliding door groove that facilitates dodge door 6,7 to open and close.

Fig. 4 is the fluid surface angle at a certain moment measured by the present invention. Fig. 5 is the change of the concrete percentage before and after passing through the reinforcement under different reinforcement distributions measured by the present invention. From the above results, the fluidity and passing capacity of the concrete under different proportions can be quantitatively determined.

Concrete implementation steps of the present invention are as follows:

(1) The test of this L-shaped box should be carried out in accordance with "determining the ratio - determining the layout of the steel bar bent frame and the length of the horizontal box - mixing concrete - filling the vertical box with concrete - standing still - opening the dodge door to control the flow of concrete - monitoring the flow process - Handle the tested concrete" process, the freshly mixed concrete must be tested within 1 minute, the resting time is preferably 1 minute, and the entire test process should be controlled within 5 minutes;

(2) This L-shaped box should be combined with other conventional equipment, such as chronograph, digital camera, electronic scale, etc., to quantify the working performance indicators of fluid concrete, and clarify its engineering adaptability and application performance;

(3) This equipment can measure the height difference of the liquid level of the fluid concrete before and after the reinforcement, measure the percentage of the coarse aggregate in the concrete before and after the test, and then quantify its flow characteristics and passing capacity;

(4) Before using this equipment for testing, you can use slump cylinders, J-rings, etc. to briefly evaluate the performance of fluid concrete, and then determine the horizontal length of the L-shaped box and the layout of the steel bent frame, etc.;

(5) Through this equipment, it is advisable to test the changes in the flow field of fluid concrete at different times, and to invert the key flow parameters through fluid surface angle and liquid level changes, using fluid mechanics related formulas or numerical simulation methods;

(6) When testing high-fluidity concrete, the concrete filling height in the vertical box should not be lower than 0.75m to ensure a complete flow process;

(7) After the test is completed, the coarse aggregate is weighed, which should be carried out after washing and drying to ensure the test accuracy;

(8) When arranging bent frames with stirrups, the stirrups should be arranged more than 5cm from the bottom of the box and lower than the middle of the vertical steel bars.

Claims (9)

1. A detachable novel L-shaped box, comprising a vertical box and a horizontal box, characterized in that, said vertical and horizontal box are connected with a detachable horizontal groove, said vertical box, The sides of the horizontal box and the horizontal tank are respectively provided with scales, the height of the vertical box is 0.5m-1m, the width is 0.2m-0.5m, and the thickness is 0.15m-0.3m; the horizontal box and the horizontal The total length of the trough is 1.2m-2.5m, the width is 0.2m-0.5m, and the height is 0.1m-0.3m; a bent frame is movably connected above the horizontal trough, and at least 2 connection holes are arranged on the bent frame , the connecting hole is provided with a steel bar extending to the bottom of the horizontal tank, and the connection between the horizontal box and the horizontal tank and the end of the horizontal tank are also provided with a movable door connected by a sliding door slot. 2. A new type of detachable L-shaped box according to claim 1, characterized in that, the two sides of the bent frame are provided with card slots for clamping the bent frame with the horizontal groove. 3. A novel detachable L-shaped box according to claim 1, characterized in that, said vertical box body, horizontal box body, horizontal groove and bent frame are all made of plexiglass. 4. A new detachable L-shaped box according to claim 1 or 3, characterized in that the horizontal tank is provided with a detachable extension. 5. A novel detachable L-shaped box according to claim 1 or 3, characterized in that the length of the horizontal box body is 0.1m-0.3m. 6. A new detachable L-shaped box according to claim 1 or 3, characterized in that, the width of the bent frame is 0.015m-0.05m, and the thickness is 0.03m-0.04m. 7. A new type of detachable L-shaped box according to claim 1, characterized in that the depth of the slot is at least 0.02m. 8. A new type of detachable L-shaped box according to claim 1, characterized in that, the steel bar is one or more of ribbed, smooth round or welded stirrups. 9. A new detachable L-shaped box according to claim 1, characterized in that the movable door is higher than the horizontal box body and the horizontal slot.