How is the slump of concrete calculated?

1. Wetting the slump cylinder and bottom plate, there should be no open water on the inner wall of the slump cylinder and the bottom plate.

The bottom plate should be placed on a solid horizontal surface, and the cylinder should be placed in the center of the bottom plate, and then step on the pedal plates on both sides with your feet, and the slump cylinder should be kept in a fixed position when charging.

2. The mixed concrete sample is evenly loaded into the cylinder in three layers, so that the height of each layer after tamping is about 1 3 of the cylinder height. Each layer is inserted 25 times with a tamper, and the insertion should be carried out from the outside to the center along the spiral direction, and each insertion should be evenly distributed on the cross-section.

When inserting concrete on the edge of the barrel, the tamper can be slightly tilted.

3. After removing the concrete on the bottom plate of the cylinder edge, lift the slump cylinder vertically and smoothly. The lifting process of the slump cylinder should be completed within 3 7s; The whole process from the start of the charge to the lifting of the slump cylinder should be carried out uninterrupted and should be completed within 150s.

After lifting the slump cylinder, the height difference between the height of the measuring cylinder and the highest point of the concrete test body after the slump is the slump value of the concrete mixture;

4. After the slump cylinder is lifted, if the concrete collapses or is sheared on one side, it should be re-sampled and measured separately; If the above phenomenon still occurs in the second test, it means that the workability of the concrete is not good and should be recorded for future reference.

At the same time of measuring the slump, the following properties of the concrete mixture can be evaluated by visual inspection, see Table 5-2, and recorded for future reference.

No need to calculate, is the use of slump barrel to on-site testing, the test procedures are available, simply put, it is a small and large tube, no bottom and no cover, step on the pedal with both feet and put it into the concrete in three layers, each layer is inserted 25 times with a rampage spiral, and finally keep the concrete as flat as the top of the cylinder.

Finally, hold the handle with both hands downward, remove your feet, lift the slump bucket upward, place the bucket vertically next to the concrete, and measure the height difference between the concrete and the slump bucket with a ruler, which is the slump bucket of concrete.

The concrete slump mainly reflects the plasticizing performance and pumpable performance of the concrete, and the main factors affecting the concrete slump are raw materials, mixing time, transportation machinery, pouring speed, pouring time, etc., in addition, the dosage of additives and the cement temperature that is easy to be ignored will also affect the index.

Self-mixing is about 7, commercial concrete is about 13, according to the drawings, the volume of walls, columns, beams and slabs is added, and you can refer to the budget book if you have a budget.

How to measure the collapse of concrete, concrete slump test, let's take a look at the operation steps.

Slump. It's not calculated, it's experimental.

Slump test method: use a flare with an upper mouth of 100mm, a lower mouth of 200mm, and a height of 300mm.

Barrel, after pouring into the concrete, tamping, and then vertically up the barrel, the process of pulling up must not touch the concrete so as not to affect the measurement data, the concrete due to its own weight to produce the phenomenon of collapse, with the height of the barrel (300mm) minus the height of the highest point of the concrete after the collapse, called the degree of collapse. If the difference is 10mm, the slump is 10.

The slump of concrete should be determined according to the structural section of the building, the content of reinforcement, the transportation distance, the pouring method, the mode of transportation, the cracking capacity and the climate, etc., and should be comprehensively considered when selecting the ratio of the coarse source, and it is advisable to use a smaller rock slump.

The slump is suitable for concrete mixtures with high fluidity (slump value is not less than 10mm), and when the slump of dry and hard concrete mixtures is less than 10mm, its consistency must be expressed by viber consistency (s).

Slump refers to the slump barrel, divided into three times to fill, poured into concrete, after each filling with a hammer along the barrel wall evenly from the outside to the inside 25 times, after tamping, smoothing. Then pull up the barrel, the concrete collapses due to its own weight, and the height of the barrel (300mm) is used to subtract the height of the highest point of the concrete after the collapse, which is called slump. If the difference is 100mm, the slump is 100.

The concrete pumping slump will greatly affect the efficiency of the construction, but in the daily construction, because many people do not understand the relevant knowledge of concrete pumping slump, it causes the loss of concrete pumping slump.

When configuring concrete, if the adaptability of the admixture to the cement is not good, it is easy to cause the loss of concrete slump. In addition, the amount of concrete admixture is insufficient, and the effect of retardation and plastic retention is not ideal, which may also cause the problem of concrete pumping slump loss.

Brief introduction. Concrete slump mainly refers to the plasticizing performance and pumpable performance of concrete, and the factors affecting concrete slump mainly include gradation changes, water content, weighing deviation of the scale, the amount of admixtures, and the temperature of cement that is easy to be ignored. Slump refers to the workability of concrete, specifically to ensure the normal progress of construction, including the water retention, fluidity and cohesion of concrete.

Workability refers to whether the concrete is easy to construct and operate, and the performance of uniform compactness, which is a very comprehensive performance, including fluidity, cohesion and water retention. The effects and workability mainly include water consumption, water-cement ratio, sand rate, including cement variety, aggregate conditions, time and temperature, admixtures and other aspects.

Influencing factors. 1. Effect of water absorption.

Due to the different storage time and batches, the water content of Shahe washed sand is unstable, and the limitation is large when the water content is determined by the test, and the water content of coarse aggregate is generally stable, but sometimes it will change, because the aggregate plant is mostly open storage, and the aggregate water content changes after the rain, and the different water absorption rate of the aggregate will cause different degrees of deviation of the concrete slump when mixing concrete.

2. Mechanical influence.

The long mixing time of concrete will increase the water absorption of aggregate, reduce the free moisture in the concrete clinker, and cause the loss of concrete slump.

The measurement system error of concrete mixing machinery will also cause the loss of concrete slump, the concrete mixing ratio is obtained by accurate calculation and adjustment after many trial matching, any kind of material due to inaccurate measurement, will make the specific surface area of the material in the unit change, the greater the change of the specific surface area of the material, the greater the loss of slump over time.

3. The impact of transportation machinery.

The longer the transportation distance and time of the concrete mixer truck, the free moisture of the concrete clinker decreases due to various reasons such as chemical reaction, water evaporation, aggregate water absorption, etc., resulting in the loss of concrete slump over time, and the concrete belt conveyor and string drum will also cause mortar loss, which is also an important reason for the loss of concrete slump.

The mold for the collapse test is a truncated conical cylinder with a height of 300 mm, an inner diameter of 100 mm at the upper mouth, and a total diameter of 200 mm at the inner diameter of the lower mouth. During the test, the collapsed cylinder is placed on the smooth ground, and the prepared mixture is evenly divided into 3 layers and filled into the cylinder, each layer is pounded, and the top surface is scraped flat. Then the drum is carefully lifted vertically, and the unsupported mixture collapses, and the distance (in cm) is the degree of collapse of the mixture.

According to the different slumps, the concrete mixture can be divided into large fluidity concrete (slump 150mm), fluidity concrete (slump 100 150mm), plastic concrete (slump 50 90mm), and low plastic concrete (hail slump 10 40mm).

This kind of question still needs to be asked, and this kind of question is also answered, which is really speechless.

Test method of slump: use a 100mm upper mouth, 200mm lower mouth, 300mm high trumpet-shaped collapse bucket, pour into the concrete and then tamp it, and then pull up the barrel, the concrete collapses due to its own weight, and subtracts the height of the highest point of the concrete after the collapse with the barrel height (300mm), which is called the collapse. If the difference is 10mm, the slump is 10.

The slump of concrete should be determined according to the structural section of the building, the content of reinforcement, the transportation distance, the pouring method, the mode of transportation, the vibration capacity and the climate.

The slump range of each grade of concrete is as follows:

1. When the concrete strength grade is less than C50, the slump should be less than 180 mm.

2. When the strength grade is greater than C50, the slump should be greater than 180 mm.

The large and small slump is determined to meet the requirements of the construction process adopted. For example, direct unloading or manpower bucket truck transfer: 6 10cm, pumping:

12 18, underwater: 16 22, self-leveling greater than 22, and there are requirements for the degree of expansion, etc.

Concrete slump refers to the amount of concrete slump during flow and is usually measured with a conical test mold. The main purpose of calculating concrete slump is to ensure that the concrete maintains consistent flow properties during construction and transportation.

The method of calculating the slump of concrete is usually determined by conducting engineering experiments. When conducting an experiment, it is first necessary to prepare a certain amount of concrete samples and conduct the test in a stable laboratory environment. The concrete specimen is then poured into a conical mold, filling the concrete with half the mold volume each time.

After filling, the mold is lifted to make the free drop of the concrete height 25 mm, repeat the operation 3 times, and then measure the height of the concrete collapse. Finally, the average of the results of the three experiments was taken as the slump of the test concrete.

In addition to experimental measurements, concrete slump calculation formulas can also help the calculator in his calculations. For the standard concrete mix, it is calculated as:

Collapse = h1-h2) h1 100%.

Wherein, H1 is the height of the cone mold before the concrete test, and the unit is millimeters; h2 is the height of the cone mould after the concrete collapses, and the unit is millimeters.

It should be noted that the calculation method and calculation formula of concrete slump are only a tool and method, and appropriate adjustments and changes need to be made according to the specific characteristics of concrete and construction conditions in practical application to ensure the fluidity and stability of concrete during construction.

In a word, the calculation method and formula of concrete collapse are of great significance in practical engineering, which helps engineers and technicians to determine the concrete mix ratio and optimize the concrete construction process. <>