CN101343159A

CN101343159A - Concrete spraying additive

Info

Publication number: CN101343159A
Application number: CNA2008101395563A
Authority: CN
Inventors: 张大庆; 张仁水; 王立华
Original assignee: QINGDAO TIANDUN BUILDING MATERIAL CO Ltd SDUST
Current assignee: QINGDAO TIANDUN BUILDING MATERIAL CO Ltd SDUST
Priority date: 2008-08-22
Filing date: 2008-08-22
Publication date: 2009-01-14
Anticipated expiration: 2028-08-22
Also published as: CN101343159B

Abstract

The invention discloses a shotcrete admixture, comprising: 13 to 15 parts by weight of cold water quick dissolving powdery methylcellulose ether or cold water quick dissolving powdery hydroxyethyl cellulose ether, 13 to 15 parts by weight of cold water quick dissolving powdery polyvinyl alcohol, 8 to 11 parts by weight of naphthalene-series powdery water-reducing agent, 1 to 2 parts by weight of mesh polypropylene fiber and 58 to 62 parts by weight of cement accelerator. The shotcrete admixture is prepared by adding the constituents into the concrete together for increasing the cohesion of concrete and viscosity of early-stage slurry, the slurry initial setting time is short, and the resilience amount of concrete can be reduced by 30 to 50 percent.

Description

A kind of concrete spraying additive

Technical field

The present invention relates to a kind of inorganic materials, especially add the admixture in the sprayed concrete to.

Background technology

20 beginnings of the century, German Application and Development sprayed concrete mortar supporting tunnel, early 1950s, the research success of simple and easy spraying machine and accelerating chemicals is for condition has been created in the application of concrete-spraying technology.To the eighties in 20th century, concrete-spraying technology develops into damp spray, wet shot, cement by the single dried spray in past to be wrapped up in sand blasting and penetrates various ways such as concrete, steel fibrous shotcrete.Facts have proved, sprayed concrete is compared with onsite concrete, easy construction is easily gone, save formwork, cast and form removal operation, make concrete conveying, cast and tamping be combined into a procedure, save manpower, shortened the duration, can also be by of the thin-wall construction construction of defeated material flexible pipe at high chamber or narrow and small operation interval.At present, the concrete spraying technique has been widely used in the supporting in metallurgy, coal, water conservancy and various underground works chamber, tunnel.

But rebound degree height, jet quality instability are to perplex the difficult problem of sprayed concrete development for a long time.In practice of construction operation, the rebound of shotcrete rate is generally more than 30%, have in addition surpass 40%, cause waste of material, also influence construction quality and construction speed.

Summary of the invention

Technical problem to be solved by this invention is: a kind of concrete admixture that can reduce the rebound of shotcrete rate is provided.

The present invention solves the technical scheme that its technical problem takes: it is that material by following weight part combines:

Water-holding agent 13-15 part, polyvinyl alcohol 13-15 part, water reducer 8-11 part, polypropylene fibre 1-2 part and cement hardener 58-62 part.Wherein:

Described water-holding agent is cold water instant dissolving type powdery methyl cellulose ether or cold water instant dissolving type powdery hydroxyethyl ether cellulose.

Described polyvinyl alcohol is a cold water instant dissolving type polyethylene powder alcohol.

Described water reducer is that naphthalene is the powdery water reducer.

Described cement hardener is an accelerating chemicals commonly used in the existing manufacture of cement, and it is to be major ingredient with the aluminum oxide clinker, adds calcining and grinding such as soda ash, Wingdale, gypsum and forms.

Described polypropylene fibre is netted polypropylene fibre, and its length is 2-15mm.

Above-mentioned each raw material is the commercially available prod.

Admixture of the present invention is applicable to the concrete dry pressure spray process.During use, admixture of the present invention is stirred according to the 6.5-8.5% ratio of cement weight and cement sand and stone, can spray.

The mechanism of action below in conjunction with each component in the admixture of the present invention illustrates positively effect of the present invention.Water-holding agent dissolving described in the admixture of the present invention is very fast, is easy to disperse, and is convenient to construction and increases concrete viscosity; Described polyvinyl alcohol (being called for short PVA) is the cold water instant dissolving polyvinyl alcohol, can improve the early stage viscosity of concrete, increases concrete sticking power; Described naphthalene water reducer can improve concrete flowability and slump, reduces water consumption, improve concrete job specification; Described polypropylene fibre (being called for short the PP fiber) is that starting material process with the polypropylene, its outward appearance is that the mutual commissure of plurality of fibers monofilament forms reticulated structure, after the polypropylene mesh fiber is put into concrete, in the concrete whipping process, horizontal binding between fibre single thread destroys through rubbing with rubbing effect of concrete self, form fibre single thread or reticulated structure and fully open, thus the effect of the polypropylene fiber concrete of realization One's name is legion.The present invention is added on above-mentioned each component combination in the concrete, can increase the viscosity of concrete force of cohesion and early stage slip, and the slip presetting period is short, can make concrete reduce the springback capacity of 30-50%.

Embodiment

Be that example illustrates technical scheme of the present invention in 100Kg cement, to add the present invention's 8% admixture below.

Embodiment one: choose powdery carboxymethyl cellulose 13.5%, polyethylene powder alcohol 15%, naphthalene water reducer 9.5%, netted polypropylene fibre 1.0% and accelerating chemicals 61%, promptly calculate according to concrete 100Kg cement amount, each amounts of components is that powdery carboxymethyl cellulose 1.08Kg, polyethylene powder alcohol 1.2Kg, naphthalene water reducer are that 0.76Kg, netted polypropylene fibre are 0.08Kg and accelerating chemicals 4.88Kg.

Embodiment two: choose powdery carboxymethyl cellulose 14.5%, polyethylene powder alcohol 14.0%, naphthalene water reducer 8.0%, netted polypropylene fibre 1.50% and accelerating chemicals 62%, promptly calculate according to concrete 100Kg cement amount, each amounts of components is that powdery carboxymethyl cellulose 1.16Kg, polyethylene powder alcohol 1.12Kg, naphthalene water reducer are that 0.64Kg, netted polypropylene fibre are 0.12Kg and accelerating chemicals 4.96Kg.

Embodiment three: choose powdery carboxymethyl cellulose 15%, polyethylene powder alcohol 13.5%, naphthalene water reducer 9%, netted polypropylene fibre 1.20% and accelerating chemicals 61.3%, promptly calculate according to concrete 100Kg cement amount, each amounts of components is that powdery carboxymethyl cellulose 1.2Kg, polyethylene powder alcohol 1.08Kg, naphthalene water reducer are that 0.72Kg, netted polypropylene fibre are 0.096Kg and accelerating chemicals 4.904Kg.

Cold water instant dissolving type powdery methyl cellulose ether is selected the MKX45000PF20L type methyl cellulose ether that Bayer A.G produces for use among the embodiment.Cold water instant dissolving type polyethylene powder alcohol selects for use Beijing sieve to build the polyvinyl alcohol of Science and Technology Ltd. or the production of sky, Shanghai plan trade Co., Ltd.Naphthalene is the FDN type naphthalene water reducer that the powdery water reducer selects for use Beijing Muhu Concrete Admixture Co., Ltd. to produce.Polypropylene fibre selects for use Shandong Tai'an Modern Plastic Co., Ltd. to produce polypropylene fibre.The cement hardener that cement hardener selects for use Beijing Muhu Concrete Admixture Co., Ltd. to produce.

The also available hydroxyethyl ether cellulose of cold water instant dissolving type powdery methyl cellulose ether among above-mentioned three embodiment replaces, and the hydroxyethyl ether cellulose HS200000 effect of selecting for use German CLARIANT company to produce is better.

Per-cents all among the embodiment all are weight percentage.

Be further checking positively effect of the present invention, on auxiliary shaft building site, Guo Tun colliery, Yuncheng, Shandong Province city, carry out concrete spraying additive with the admixture of above-mentioned three embodiment ratios and test.The Guo Tun colliery is that a family newly opens the colliery, is carrying out [underground at that time.Test-results sees Table 1.

The different proportioning admixture of table 1 test-results

Annotate: Comparative Examples is the proportioning of sprayed concrete when not adding admixture.

During sprayed construction, 4 people's material loadings, 1 people picks up on the opening for feed double-edged fine-toothed comb except that the bulk particle, and 1 people holds lance ejection.Spray the site operation personnel and all wear dust protecting mask, spray hand and also be with eye-protection glasses.Spray hand and open tap water earlier, slowly open high-pressure air by 1 people again, air pressure is transferred to 0.4MPa, the injection hand will spray basal plane with high pressure water earlier and clean one time, and the material loading personnel begin material loading, injection beginning.

Spraying machine is the PC5U type rotor-type shotcrete machine that Changzhou Wujin Meccanica Generale S. R. L produces, and per hour can spray 4-5m ³Concrete.

Material loading is put three bulk paulins in the bottom of jet face before spraying, and is used for collecting injection resilience material.

As can be seen from the table, when the concrete of interpolation admixture of the present invention sprayed, rebound degree obviously reduced, and especially when each component was selected the ratio of embodiment two for use in the admixture, rebound degree was lower relatively.

Precaution when the present invention constructs: during spraying operation, what are extremely important to add water.Because the singularity of spray technology, water is added by the gun slot place, and amount of water is judged the sprayed concrete surface appearance with operator's experience basis entirely, controls by regulating water valve.When trickling, slippage, drawing crack appear in the sprayed concrete surface, show that water cement ratio is excessive, need to reduce amount of water; If the surface occur in dry spot, the operation dust big, when springback capacity is big, show that then water cement ratio is too little, need in time add big yield; Work as surfacing, be water light pool shape, dust and resilience show that water cement ratio is suitable more after a little while.

Claims

1, a kind of concrete spraying additive is characterized in that, it is that material by following weight part combines:

Water-holding agent 13-15 part, polyvinyl alcohol 13-15 part, water reducer 8-11 part, polypropylene fibre 1-2 part and cement hardener 58-62 part; Wherein:

Described water-holding agent is cold water instant dissolving type powdery methyl cellulose ether or cold water instant dissolving type powdery hydroxyethyl ether cellulose;

Described polyvinyl alcohol is a cold water instant dissolving type polyethylene powder alcohol;

Described water reducer is that naphthalene is the powdery water reducer;

2, the concrete spraying additive that selects as claimed in claim 1, it is characterized in that it is that material by following weight part combines: 62 parts of 14.5 parts of carboxymethyl celluloses, 14.0 parts of polyvinyl alcohol, 8.0 parts of water reducers, 1.50 parts of polypropylene fibres and accelerating chemicalss.