Concrete pumping building and construction is a really usual construction technique, and great pumping efficiency is the required functioning performance of concrete. Concrete pumping performance is influenced by the residential properties and also blend ratio criteria of resources such as cement, mineral admixture, sand, stone aggregate, water as well as admixture.

Caste Material

During the pumping process, the fluid stage material in the concrete is the medium of the pumping pressure transmission. The duty of cementing product in concrete has 2 facets. On the one hand, it develops a slurry with water, fills and also concludes the accumulation surface, and keeps the strong stage wrapped by the liquid stage throughout the pumping procedure; On the other hand, the lubrication effect of the sealing product slurry can efficiently minimize the rubbing resistance between the concrete and also the pipe as well as the components of the concrete itself, and has great fluidness in the pumping procedure.

( 1 )Water retention of the concrete product

The water retention of sealing product has a certain impact on concrete pumping. The sealing product with great water retention will not precipitate and also hemorrhage water after the pumping stress, as well as the pump loss of concrete depression is tiny. Fly ash has excellent water retention, while slag powder has inadequate water retention.

( 2 )Dosage of gelatinous products

The amount of cementing product for pumping concrete ought to not be inadequate, the not enough amount of sealing product will certainly impact the suction performance of the pump, and boost the resistance of concrete pumping, as well as the water retention of the combination is poor, simple to hemorrhaging, segregation triggered by pipeline connecting.

In a similar way, the quantity of sealing material leads in the rise of concrete viscosity and the rise of pumping resistance. The quantity of sealing product is likewise affected by the grain form and grading of aggregate For the accumulation with reduced void percentage, the quantity of sealing product is reasonably low. The same bit size, rated pebble (all-natural sand) and crushed rock (mechanical sand), the quantity of gravel (mechanical sand) is above the pebble (all-natural sand).

Additionally, the quantity of cementing product is additionally connected to the size of the communicating pipeline and also the sharing distance. Generally speaking, the longer the conveying range is. The smaller sized the diameter of the sharing pipeline is, the higher the demands for the fluidness, lubrication and water retention of the concrete are, as well as the better the quantity of cementing product is. Typically talking, the amount of concrete product for pumping concrete must not be less than 280 kg/m3.

Fine accumulation

( 1 )The selection as well as quality of fine accumulation

Generally speaking, the surface of natural sand is smooth, and also the pumping performance is far better than that of harsh mechanical sand. The pumping performance of tool sand is much better than that of rugged sand and fine sand, the concrete communication of coarse sand, bad water retention, easy to segregation brought on by partition; On the one hand, the thickness of fine particles in the great sand boosts the pumping resistance, on the other hand, the specific area is larger. When the slurry is unmodified, the slurry of the accumulation is easy to thin as well as the friction in between the aggregate increases. At the same time, the fragment content of 0.315 mm ought to not be less than 15%, the medium as well as reduced toughness quality concrete is typically managed at around 20%, and the quantity of gel material should be increased when the content wants.

( 2 )Particle grading of great accumulation.

The particle grading of accumulated refers to the distribution of all degrees of size particles in the aggregate. Excellent particle grading of great bone can reduce the complete surface and also space each quantity to the lowest value. Pump concrete need to select the great aggregate with excellent grading as well as reduced void ratio, to ensure that the accumulation can get excellent pumping efficiency with less cementing material. In manufacturing practice, when the particle grading of great aggregate can not satisfy the needs, the fine accumulation with big excellence modulus as well as the fine accumulation with little fineness modulus are commonly used in a specific percentage to accomplish the minimal space.

( 3 )The quantity of great aggregate used

In the pumping concrete, the mortar composed of slurry and great accumulation loads the void between the crude accumulation, and also packages the surface area of the coarse accumulation to play a lubrication role, for that reason, the amount of great accumulation has a great relationship with deep space proportion of the rugged accumulation When deep space rate of coarse accumulation is huge, extra mortar is needed to fill up and also wrap the accumulation, so the sand rate is large; deep space proportion of coarse aggregate is tiny, the quantity of mortar for filling up and also covering the crude aggregate is tiny, and the sand price is fairly small. As a result, the coarse aggregate quality fit, the void rate is lower, the optimum sand price is lower.

Crude accumulation

( 1) The range and high quality of crude aggregate

When the mix parameters are the same, the surface area of the pebble is smooth as well as the concrete is better than the artificially crushed gravel. The sheet web content of needles in crushed rock is too much, resulting in a rise in pumping resistance, very easy to cause the blockage of the sharing pipeline, the basic sheet content of needles ought to not go beyond 10%.

( 2) The optimum bit dimension of the rugged aggregate

The optimum particle size of crude aggregate for pumping concrete is limited by the minimal diameter of the conveying pipe. The optimum bit size of stone ought to not go beyond 1/ 3 of the diameter of the pump pipe, as well as the maximum fragment size of gravel ought to not surpass 1/ 4 of the size of the pump pipeline. A small amount of overdiameter aggregate is permitted, but the percentage of this overdiameter accumulation ought to not be more than 5%, and also attention should be paid to suitably boost the sand rate by 1% ~ 2%.

( 3) Fragment grading of crude accumulation.

The rugged accumulation of pumping concrete is neither the smaller the much better, nor the smaller sized the bit content the far better, the most crucial grade coordination, the most affordable void proportion. The pumping capability of quality matching concrete of crude aggregate is very essential, especially for long-distance pumping. When the grading of coarse accumulation is missing out on, occasionally increasing the amount of sealing material does not improve the pumping result. When rugged aggregate appears intermittent grading, the blending method enhances accumulated grading.

( 4) Quantity of rugged accumulation used

The influence of the dosage of crude aggregate on concrete pumping capability is generally shown up in pumping pressure and also suction efficiency. In practice, as long as the sand material is well regulated, the amount of crude accumulation is regulated, as well as the aspects influencing the sand rate have the following elements:

1. The maximum particle dimension of coarse accumulation increases to lower the sand price suitably.

2. The sand price of crushed rock concrete is 2% ~ 3% larger than that of pebble concrete.

3. The sand fineness modulus comes to be larger, the sand rate is enhanced appropriately, the excellence modulus is reduced, the sand rate is decreased properly, the general excellence modulus changes 0.2, the sand price adjustments concerning 1%.

4. The boost of the amount of cementiated product can lower the sand price properly. Generally, when the quantity of cementiated product boosts by regarding 30 kg/m3, the sand price must be minimized by 1%.

Adhesive

There are many sort of admixtures, which can enhance the concrete pumping representative add gas agent, water reducer, superplasticizer, retarder. The amount of admixture differs substantially with various ranges, and also the improper dose is easy to create pipe stopping or various other quality mishaps.

Water lowering agent is to decrease the water usage with the slump the same, as well as can properly improve the fluidity of concrete, boost the pumping efficiency. Amongst them, the polycarboxylic acid system effective water lowering representative has great diffusion security, and also the big liquid concrete (depression 200mm) has little loss, which makes up for the concrete slump loss of the typical naphthalene system reliable water minimizing agent, very easy water loss as well as other problems, and is challenging to happen pipe blockage.

Air removal representative remains in the procedure of concrete mixing, can introduce a lot of uniformly dispersed small bubbles, in order to decrease the partition of concrete blend, improve the ease, so as to enhance the concrete pumping performance. Nevertheless, the air web content of pumping concrete with gas-type admixture must not be greater than 4% to stop the decrease of toughness.

Retarder is an admixture that postpones the setting time of concrete, regulates the loss of concrete downturn, and improves the upkeep ability of concrete job.