Dry powder mortar refers to dry and screened mortaraggregate(e.gQuartz sand）、Inorganic cementitious material(e.gcement）It is physically mixed with additives (such as polymer) in a certain proportionGranularOr powder, transported to the construction site in bags or in bulk, and directly used after mixing with water.Also called mortar dry powderDry mixed mortarDry mixed powder, some buildingsAdhesiveIt also belongs to this category.Dry mortar plays a role in bondingGasket, protection and decoration, building and decorationengineering application Very extensive.
Self leveling materials, repair mortar, ground hardening materials, etc.
advantage
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Joint sealer of dry mortar series
Relative toConstruction siteThe prepared mortar and dry mortar have the following advantages:
(1) Stable and reliable quality, which can meet different functions andPerformance requirementsAnd improve the project quality.
(2) The improvement of efficiency is conducive to the application of automatic construction machines and tools, and changes the backward way of traditional building construction.
(3) YesNew wall materialsIt has strong adaptability and is conducive to the promotion and application of new wall materials.
Ordinary silicatecement、High alumina cementSpecial cement, gypsum and anhydrite.
organic adhesive
Dry mortar series benefit mastic
cement mortarIt is a very hard, brittle and poor flexible material, which must be used in many construction of modern buildingspolymerThe mortar shall be modified to meet the construction requirements.In the 1930s, people began to apply the two-component system, and many problems easily appeared in the two-component system, mainly because it was difficult to accurately control the dosage of polymer emulsion.The reasons for the mistakes include lack of experience and training of workers, or cutting corners to save costs.In addition to the difficulty in using the two-component system, the increase in additional costs and the difficulty in material flow are also one of the reasons.In 1953, German WCAKER CHEMIE invented redispersible powder, which made it possible to produce polymer modified dry powder mortar, now known asOne component system。Redispersible powders are obtained byspray drying Special water-based emulsion based onVinyl acetateFat-ethylenecopolymerAnd the polymer producedAdhesive。After mixing or dispersing with water, this powdered organic adhesive can return to its original aqueous emulsion state and maintain the typical characteristics and functions of mechanical adhesive, so it is called redispersible powder.After partial evaporation of water, polymer particles coalesce to form a layer of polymer film, which acts as an adhesive.According to the different proportions, the use of redispersible polymer powder to modify dry mortar can improve theBonding strengthAnd improve the flexibility and flexibility of mortarDeformability, bending strengthWear resistance, toughnessCohesionAnd density andWater retention capacityAnd constructability.
four point oneCellulose etherCellulose ether as thickener andWater retaining agent。Although the addition ratio is very low (0.02% - 0.7%), it is very important.The cellulose ether used in dry mortar is mainly methylHydroxyethyl celluloseEther (MHEC) andMethyl hydroxypropyl celluloseEther.abbreviationMC, MC characteristics: adhesion and workability are two factors influencing each other;Water retention, to avoid rapid evaporation of water, which can significantly reduce the thickness of the mortar layer.
4.2 Other additives
1、Starch ether: It can increase mortar consistency.
2、Air entraining agent: Introduced into mortar through physical actionMicrobubbleThe density of mortar is reduced and the workability is better.Mainly fatsulfonic acidSodium salt andsodium sulphateThe salt addition ratio is 0.01% - 0.06%.
3. Coagulant holding agent: use it to obtain the expectedsetting time 。CommonCalcium formateThe addition ratio is 0.5% - 2.5%.
5. Hydrophobic agent（Waterproof agent: It can prevent water from seeping into the mortar, and the mortar can still be kept open forsteamDiffusion.Mainly used withHydrophobicityThe polymer can re disperse the powder, which is characterized by that it will not be washed away from the mortar by rain after many years, so it has the advantage of significantly extending the service life and improving the adhesion between the hardened mortar and the substrate.
7. Fiber is divided intoLong fibreAnd shortfibre。Long fiber is mainly used for reinforcement and reinforcement;Short fibreUsed to affect the performance andwater demand。
Firstproduct qualityHigh.Dry mortar has solved the problemTraditional craftIt is difficult to grasp the proportion of the prepared mortar, which leads to problems affecting the quality. The measurement is very accurate and the quality is reliable.Because the mortar for different purposes has different requirements on the properties of materials such as anti shrinkage, anti cracking, heat preservation and moisture resistance, and the workabilityWater retention、Setting timeIt is also different.These characteristics can only be achieved by strict preparation according to scientific formula. Only dry mortarProduction processThis requirement can be met.Because of the accurate measurement and quality assurance, the project quality is significantly improved, the construction period is significantly shortened, and the labor consumption is reduced after the use of dry mortar.
Secondly, the variety is complete.According to different requirements of construction, many products and specifications have been developed.The products can meet the needs of various buildingsMasonry mortar、Plastering mortar、Floor mortar；According to different requirements of building quality, specifications can be divided into M2.5, M5, M10, M15, M20, M25, M30Consistency, layering degree, density, strengthrequirementThe package can also be divided into 5kg, 20kg, 25kg, 50kg and several kindsbulk vehicleSealed delivery.
Besides, it is convenient to use.It's like eatinginstant noodlesSame, take it as needed, add about 15% water, mix it for 5-6 minutes, and use the remaining dry powder as standbyquality guarantee periodHowever, the strength did not change significantly after being placed for 6 months in the test.currentmarket valueAbout 250 yuan/ton.
development
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problem
According to the current development of dry mortar in China, it has defects in the following aspects.
2. The technology is immature.Due to the lack of complete corresponding specifications for production and construction, the promotion of dry mortar in the project is restricted.And there is no corresponding technologyGuarantee and guidanceConstruction and immature construction technology also affect its development in varying degrees.
3. The variety of mortar is not rich.More than 1000 kinds of dry powder mortar have been developed abroad, but there are less than 100 kinds in China. Therefore, the mortar is not matched and does not meet the function in use, which has a very adverse impact on the promotion and use of mortar.
4. Large investment.dry mortar production line The one-time investment is too large for ordinary enterprises to bear, so dry mortar production enterprises are relatively poor.Moreover, due to thetechnical contentHigh, in useLocal materialsThere are certain difficulties in the promotion of dry mortar.
our countrynational economyandsocial developmentThe direction is to build a resource-savingEnvironmentally friendly societyTo promote economic, social and environmental protectionCoordinated development。The 11th Five Year Plan period is a critical period for China to build a moderately prosperous society in an all-round way, and also a critical period for turning economic and social development into a scientific development track.
Dry mortar is directly used in variousarchitectural engineering, as aNew building materialsIts development is closely related to the construction industry. The development goals and characteristics of the future construction industry will directly affect the development of dry mortar.
The characteristics of future construction industry development are as follows:
1. The total construction volume continues to grow
With the development of our countryUrbanization processAcceleration and construction ofestateWith the vigorous development of, China's existing construction volume has reached more than 40 billion square meters.In the next 15 years, the construction industry will remain relatively highGrowth rate。
As China steps into the historical process of building a well-off society in an all-round way, it can be expected that in the next 15 years, China's capital construction, technological transformation, real estate, etcInvestment scale of fixed assetsIt will remain at a high level during the "Eleventh Five Year Plan" period. The per capita residential area in China's cities and towns will reach 28 square meters and that in rural areas will reach 33 square meters. About 8 billion square meters of new residential area will be needed.By 2020, the per capita residential area in urban areas will reach 35 square meters, and that in rural areas will reach 40 square meters. A total of more than 20 billion square meters of new residential buildings will be needed, which will provide a huge contribution to the development of the construction industryMarket space, alsoDry mixed mortarThe development of the industry provides a huge market foundation.
In today's energy shortage,Building energy consumptionThe proportion in the total energy consumption of the country has risen from 27.6% to more than 33%Energy saving buildingIt has become the focus of construction industry development in the next few years.Building energy conservation is to alleviate the contradiction of energy shortage in China and improve people's livesWorking conditionsReduce environmental pollution and promote economysustained developmentOne of the most direct and cheapest measures.Specifically, it is necessary to use more effective building materials to reduce heat lossenergy conservationThe purpose of.
The goal of building energy conservation during the 11th Five Year Plan is to save 101 million tons by 2010Standard coal, reducing emissions by more than 400 million tonscarbon dioxideGas.By comprehensively promoting building energy conservation, urban buildings will reach the design standard of 50% energy conservation by 2010megacityAnd some large cities take the lead in implementing the standard of 65% energy conservation;Carry out urban existing residence andPublic buildingsOfEnergy saving transformation；25% of the renovation area of large cities has been completed,Medium-sized city15% complete,small city10% complete
Special mortar for wall insulation system in dry mortar, with highbond strength , high flexibility, lowWater absorptionAnd widely used inBuilding insulationThe implementation of the goal of building energy conservation in China will strongly drive the rapid development of the mortar market for thermal insulation.
3. Building quality has improved significantly
With peopleliving standardWith the improvement of, the requirements for building quality are getting higher and higher.The application of dry mortar can greatly improve the project quality.Due to the influence of the technical proficiency of the construction personnel and the quality of cement, sand and other raw materials, the mortar allocated at the construction site, whether masonry mortarPlastering mortar, or ground leveling mortar, and buildings often appearplastering mortar Cracking phenomenon (even the most traditionalClay brickThe use of cement mortar plastering on the wall will also cause a large area of cracks), resulting in unstable engineering quality, strength not meeting the requirements, and even poor quality, which has become a buildingCommon quality problems。On the other hand, in order to reduce the use of clay bricks, the state vigorously promotes new wall materials. Because of the characteristics of this material, ordinarycement mortarIt can no longer meet the needs of masonry and plastering.The dry powder mortar is produced in an industrial waymix proportionStrict control, raw material selection, accurate measurement and even mixing can ensure stable and reliable mortar quality.Architecturequality requirementThe improvement of will guide the transformation of traditional mortar to dry powder mortar.Dry mortar will be subject tonational policyAnd gradually become the favorite of the market.
The characteristics of this building structure will not be easily changed in a short time.Therefore, a large amount of ordinary plastering mortar and ordinary plastering mortar will still be needed for a long time in the futureMasonry mortar, so thatDry mixed mortarApplications provide broad market space anddevelopment potential。
（3） Policy environment analysis
our countryReady mixed concreteConsumptionIt is through compulsory implementation that it has risen sharply, which has been recognized by the society.Development history, promotion experienceProduct attributes、Policy environmentThe engineering conditions are very similar to premixed concrete, and the introduction of mandatory measures for market application is just a matter of timing.With the implementation of the national sustainable development strategyprotect the environment. The relevant national departments will summarize the increasing importance of ensuring project qualitycommercial concrete We will develop our own experience and take a fast and efficient way to promote dry mortar.
The next 20 years will be the best period for the development of dry mortar in China. The state will formulate policies to promotesolid waste And other main raw materialsDry mixed mortar。At present, the promotion of dry mortartechnical conditionsIt is basically mature.
1. Scientific research is the first, which provides a foundation for the development of dry mortartechnical support
Dry mixed mortarapplied technologyAchievements have been made in the research, and the application technology has become increasingly mature.
In 1994,ShanghaiThe city has started scientific research on dry mortar, and successfully developed dry mortar with mortar thickening powder technology as the core.This technology is very suitable for domestic application, and is the same as foreign technology (nitrificationLime powderCellulose ether) can reduce the material cost by about 50%, and the material cost is only 100 yuan/ton.At present, this technology is widely promoted in Shanghai.
In 2002,BeijingcityBulk cementofficechoiceBeijingTiantongyuanResidential quartersThe 2000 square meter fire control complex building is a pilot project, and the bulk dry mortar is used for the first time in Chinaengineering constructionThe experience of dry mortar in transportation, storage, use and construction equipment manufacturing has been found out through the pilot project, and the development of construction equipment has been carried out on this basis.
2. Advanced cityTechnical regulationsBecome the technical support for the nationwide promotion of dry mortar
Shanghai, Beijing, Guangzhou and other cities have formulated the technical regulations for the application of dry powder mortar with local characteristics, providing a technical support for the promotion of ordinary dry powder mortar.
3、Production equipmentThe manufacturing level is improving, effectively reducing the entry threshold
Compared with a few years ago, ChinaDry mortar production equipmentThe level has been significantly improved, and it has the capability of equipment localization, which reduces the capital and equipment threshold for enterprises to enter the field of dry powder mortar, thus providing guarantee for the vigorous promotion and application of dry powder mortar in China.
4. Large foreign enterprises have brought advanced technology and experience to China
In recent years, overseasDry mixed mortarProduction giants have increased their investment in capital and technology in China. Almost all foreign dry mortar production giants have branches or offices in China, such asHeidelberg Cement GroupMaxtHenkel, GermanyXi'an Hangang Chemical Co., LtdIn, Motec and other German companies established dry mortar production equipment, logistics and construction machinery plants in China, and Wacker also established polymers for dry mortarColloidal powderManufacturer.In addition, Saint Gobain has also built a dry mortar factory in China.
Foreign dry mortar production giants enter the Chinese market, not only forChinese architecture High quality building materials have been introduced into the market, which has also played a demonstration role for China's dry mortar industry.The world's advanced concepts, technologies and management experience they brought have provided valuable reference for China's dry mortar enterprises, shortening the gap between China anddeveloped countryAt the same time, it has played a good role in the promotion of dry mortar in ChinaFacilitation。
5. Impact of main raw materials
Sand is the main raw material for the production of dry mortar, and the production of dry mortar uses a large amount of raw sand.our countryBuilding sandThe annual demand is more than one billion tons. With the massive exploitation, China's natural resourcessandResources have been quite scarce, the price of sand has become higher and higher, and the contradiction between supply and demand has become prominent.
Dry mortar
The dry mortar can use artificial sand and stone instead of natural sand and stoneProduct qualityThere is no adverse effect.Artificially manufactured sand and gravel are leftovers or cement plants mined from some minestailingsWaste limestone, orConstruction waste、gangue, steel slag and other industrial solid wastes are broken and screened to meet the particle size requirements for dry mortar production.In this way, waste can be recycled and environmental damage can be reduced, which is fully in line with China's developmentcircular economyConcept.A large amount of limestone waste andIndustrial wasteIn the next 15 years, the amount of industrial solid waste will also be large, which can fully ensure the adequate supply of dry mortar raw materials.Beijing Teshou Dry Mixed Mortar Building Materials Factory, located in Beijing Shougang, is a manufacturer of dry mixed mortar with steel slag as aggregate, and its products have beenThe National StadiumIt has been used in the project and achieved good results.
Based on the above analysis and the prediction of China Building Materials Planning and Research Institute, dry mortar in the next 10 yearsMarket demandIt will grow at a rapid rate, then slow down, and then maintain a relatively stable market space.It is estimated that the consumption of various dry mortar will be about 70 million to 80 million tons in 2010.exceptSpecial mortarForeign, China's rural areasMarket futureIt is impossible to become dry mortarconsumer market, dry mortar is mainly used in citiesHousing constructionFor maintenance and other projects, dry mortar accounts for 30% of the total mortar demandMarket capacityIt is expected to reach about 300 million tons.
prospect
Although dry mortar meets various resistance in the process of promotion and use, its history of replacing traditional mortarInevitabilityIt is difficult to change.Not only Shanghai, but also other large and medium-sized cities have shown great interest in the use of dry mortarscientific and technical workerContinuousScientific and technological progressWill create favorable conditions for the development of dry mortar.Likecommercial concrete It will usher in a brilliant spring.From today'sDevelopment trendIn the future, the development of dry mortar in China will mainly focus on the following points:
1. The dry powder mortar mainly uses industrial wastes and local materials.Fly ash, slagWaste rockPowder, refinery waste residueBentoniteThe utilization of dry mortar can not only reduce the cost of dry mortar, improve the performance of mortar, but also help protect the environment and save resources.
2. Develop new varieties.Only by developing all kinds of mortar that are comprehensive and meet the needs of the market, can the scope of use be unrestricted and create favorable conditions for its smooth promotion.With the emergence of special mortar and special mortar, it not only drives the development of dry mortar, but also creates conditions for the development of other industries.
3. Develop your ownProduction process。At present, the production process of dry mortar is not mature in China. The production lines of general production enterprises are introduced from abroad, and the investment in a production line is generally 20 million to 30 million yuanRMB, expensive.Only by developing the production process in line with China's national conditions can we create conditions for the overall construction of dry mortar enterprises, which not only reduces theInvestment cost, and reducedproduction costs。
4. AndWall materialCoordination.The country has been committed to promoting the use of new wall materials, so it is necessary to develop special mortar matching the main block materials currently used.According to relevant data, the problems of the original mortar in the use of new wall materials are: a. poor construction performance of mortar,BlockExcessive water absorption during masonry,drying processMiddle blockwater lossThe wall cracks due to secondary drying shrinkage;Mortar masonry is not full, and there are quality problems such as cavities.b、The adhesive force of mortar after drying and curing in new wall materialsClay brickDue to the difference between the two, the bond force is insufficient, which leads to the wall cracking easily under the influence of deformation stress.
