A c25 super slump concrete

Abstract

The invention discloses a C25 ultra-slump concrete, which relates to the field of concrete. The concrete has good compatibility, there is basically no loss in slump within 3 hours of leaving the machine, and the slump loss is small after 5 hours, and the work performance is good: it can still meet the construction requirements for construction sites with long production transportation distances and waiting times; During the process, it avoids the situation that the construction party needs to add water to adjust the working performance of the concrete, so that the strength of the concrete is guaranteed; the overall quality of the concrete is improved, and it helps the construction party to build high-quality projects, which can produce good economic and social benefits. The C25 ultra-slump concrete, per m 3 Concrete includes the following components: 140‑160kg cement, 110‑130kg limestone powder, 30‑50kg mineral powder, 140‑160kg river sand, 710‑730kg machine-made sand, 1020‑1040kg gravel, 3‑5kg admixture and 150‑170kg Water; said per kg admixture comprises the following components: 70-90g water-reducing mother liquor, 410-430g slump-preserving mother liquor.

Description

technical field [0001] The invention relates to the field of concrete, in particular to a C25 ultra-slump concrete. Background technique [0002] Today's infrastructure construction in my country has entered a stage of rapid development. The construction of high-speed railways, highways, hydropower, nuclear power, large bridges and other projects has brought new opportunities for the development of high-performance concrete. The development of the construction industry and the rise of labor costs have made ready-mixed concrete account for an increasing proportion of concrete construction. However, the increasing shortage of high-quality sand and gravel aggregates, the use of a large amount of mud-containing aggregates, and the use of a large number of mineral admixtures make the cement composition more complex, resulting in excessive loss of concrete fluidity. The loss of concrete fluidity not only seriously affects the construction progress of the project but also deterior...

AI Technical Summary

Problems solved by technology

[0003] In order to improve the fluidity of concrete, the main ways to improve the fluidity of concrete at home and abroad include changing the mixing process, adding retarders, water-reducer granules, and compounding reactive polymers, but these slump-preserving methods can only partially meet the requirements of ordinary concrete. The short-term slump requirements are difficult to meet the high temperature and long-distance transportation of some special engineering concrete.

[0004] The traditional water reducer has good initial dispersibility, but poor dispersion retention ability, while the new slump retaining agent has poor initial dispersibility, and the later growth rate is large, showing a trend of "increase first and then decrease", which is easy to cause concrete segregation Bleeding, and the slump retention time is not long enough, even if it is used in combination, it is difficult to meet the long-term slump retention requirements of high-temperature and long-distance transportation concrete, thus giving some special projects such as the Hong Kong-Zhuhai-Macao Bridge and the concrete in high-temperature areas such as Xinjiang Difficulty with application

[0005] To sum up, the method of changing the concrete mixing process to improve the fluidity of concrete is not only costly, but also unsatisfactory; the traditional compound retarder technology has a certain effect, but the effect of continuing to increase the coagulant retarder is general , It will also affect the early strength of concrete; the granulation method of water reducing agent will increase the cost, and the technical difficulty is relatively large; and although the new type of slump-preserving admixture can meet the needs of ordinary concrete, it is difficult to meet the requirements of high temperature and long distance conditions. The demand for long-term slump protection (more than 4h) of concrete

[0006] The loss of working performance of concrete is a problem often encountered in the use of commercial concrete, especially in summer, due to the characteristics of commercial concrete production, transportation and long waiting time, coupled with high external temperature, it is easy to cause a large loss of working performance, concrete It is difficult to pump after arriving at the site. What is more serious is that in the actual pouring process, some construction units often add water wantonly at the construction site for the convenience of construction, resulting in a decline in the quality of the concrete, which leads to unqualified strength of the building. incalculable economic loss

[0007] For example, the adaptability of some cements is very poor, which is manifested by the large slump loss of concrete, dry and hard concrete, poor fluidity, and even worse construction performance than second-generation products; most commercial concrete mixing plants are now built in cities In addition to the increasing urban congestion, it often takes one or two hours for fresh concrete to arrive at the construction site, plus the waiting time, it often takes three or four hours to unload. The slump loss of concrete is too large, it is already difficult to unload, causing the next truck to wait again, and finally forming a vicious circle

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