Concrete pumping concrete and pipeline design of key technologies

Concrete pumping concrete and pipeline design of key technologies
    Summary: I tenders estuary Temple reservoir reinforcement project engineering background, concrete pump conveying concrete plugging problem through the project 2 units HZS120 concrete mixing plant onproduced concrete mix, pipeline design, The plugging reasons analysis, development of a concrete pumping concrete and pipeline design guidance programs, to provide a reference for the use of similar concrete pumping equipment.Keywords: concrete pump concrete mixing plant concrete mixer pipeline design
    The estuary Temple reservoir Shaanxi Province Wuding River, a tributary of the road and the last a focus on medium-sized reservoirs, total reservoir capacity is about 6 1 4 00 000 m 3 0 estuary Temple reservoir reinforcement project I tenders including New Spillway and Sand hole, water tower Hekou putWater tower traffic bridges. New Spillway and Sand hole design for long 287.8 7 km cross section round R = 1.5 m circular pressure tunnel, then energy consumption by the import segment, the import lock chamber segment, hole posture export Gate Chamber and export from front segments. Which tunnel grouted rockbolting, tunnel reinforced concrete lining of the tunnel backfill grouting, tunnel consolidation grouting concrete pump conveying concrete to complete. Through research, analysis, practice, summarizes work out the following concrete pumping concrete pipeline design guidance program.The basic requirements of a concrete pumping concrete
    Compulsory concrete mixing plant production requires the right concrete batching plant, which is smooth and economic determinants of the concrete pumping operations. Coagulation ± fit than including: aggregate gradation, cement content, concrete consistency of the three elements, these three elements intersect work.For example: When the fine aggregate or cement content concrete pumping, it is desirable with the ideal PLD4800 batching machine aggregate measured separately aggregate ratio, increase the sand content, and more water method to improve concrete pump sex; improper aggregate gradation, the sand content is too low, or too many flaky gravel increase of some 2.5 ~ 0.5cm pebbles, change the coarse aggregate gradation, and can also be used more cement or water, some improve its concrete pumpability.1.1 the concrete consistency (slump)
    Consistency of concrete by a number of factors: the water-cement ratio of concrete, aggregate gradation and nature, time, temperature, cement properties and admixtures, but the main influencing factors are the water-cement ratio of the concrete. The consistency of the concrete pumping concrete commonly used to measure concrete slump values ​​to determine. Slump directly reflect the size of the water-cement ratio concrete and concrete pumping performance.1.1.1 slump concrete pumping pressure
    The concrete slump reflect the size of flow performance is good or bad. Therefore, the concrete transport resistance decreases with increasing slump. In other words, the slump smaller concrete pumping greater the pressure, especially slump value in the 15cm or less, more this change is obvious.1,1.2 concrete pumping concrete slump range of concrete pumping volumetric efficiency
    Concrete pumping concrete slump range of 6 ~ 23cm, but the practical application of the general control within the range of 8 ~ 18cm, this range can be concrete pumpability best absorption effect best. For long-distance, large high concrete pumpingGeneral control 15cm left, because:
    (1) the slump is too small, concrete pumping pressure will increase and cause increased wear of concrete pumps and cause plugging;
    (2) slump too large, on the one hand the role of the large pressure concrete easy segregation, resulting in plugging; other hand, the impact absorbing performance of the concrete pump, so that the concrete produce segregation in the absorption process, it is difficult to The concrete pumping slurry leakage and because the the dispensing valve Mifengbuyan easily.
    (3) the concrete slump assurance measures:
    a strict control of the concrete mix;
    b shorten the transit time of the concrete before the concrete pumping;
    c ensure the homogeneity of the concrete.
    (4) the use of cement in line with national standards, and generally may not be concrete pumping quick-setting concrete.The 1.2 Aggregate ingredients batching machine of the machine using PLD4800 independent measurement1 .2.1 fine aggregate
    (1) the variety and quality of fine aggregate. Fine aggregate can be divided according to the source of river sand, sea sand, mountain sand, artificial brokenSand. River sand concrete pump is the best artificial sand surface rough, sand bad shape, concrete pump less, but its good water retention.(2) a fine aggregate size requirements.
    Fine aggregate can be divided into sand, fine sand, coarse sand in three categories, in the sand concrete pumps best. The use of fine sand. The need to increase the concrete, cement and water consumption to accelerate concrete pump machine wear, grit prone segregation cause the pipes get clogged(3) the amount of the fine aggregate.Transport in concrete pump concrete, the amount of the fine orthopedic porosity great relationship with the coarse aggregate, cement mortar must be filled with coarse orthopedic gap is not easy to segregation. If the sand low rate of voids by the cement to supplement this must increase the amount of cement, the same concrete Yi Qinshui and segregation, sand ratio is too large, the fluidity of the cement mortar is greatly reduced, a significant increase in the pumping resistance of concrete . Therefore, under certain conditions, have the best sand ratio. The sand rate case as long as the amount of cement is a corresponding increase in concrete concrete pump is no significant effect. If the coarse aggregate gradation and the maximum aggregate size of the larger the best sand ratio is lower. Under normal circumstances,Concrete sand ratio can be selected (see Table 1) range.Table 1 Recommended the sand rate table (96Concrete
 The aggregate size of the sediment concentration concrete aerated agent concrete mixing gas agentPebble gravel pebble gravel
        

混凝土 骨料粒径         含沙量	掺加气剂混凝土		无加气剂混凝土
	卵石	碎石	卵石	碎石
15	48	53	52	54
20	45	50	49	54
30	42	45	45	49
40	40	42	42	45

Attention! Sand the rate should be a minimum of not less than 40%, or concrete pumping is very difficult.