The national development and Reform Commission in July 3, 2004thirty-eighth announcement, approved the" concrete porous brick" for the national building materials industry standard, standard number is JC943-2004, the standard is carried out at rising on November 1, 2004, by the China Building Materials Industry Publishing house.
According to the State Economic and Trade Commission of China Trade and industry 73 date file issuing plan, formulate concrete porous brick mandatory occupation standard task from Zhejiang province of new wall materials industry association, building materials industry and Technical Supervision Research Center (formerly the National Building Materials Industry Standardization Institute) is responsible for the relevant scientific research units, organizations and enterprises to participate in drafting, technical focal point for Xi'an walling material research & Design institute.
Concrete perforated brick is a kind of new wall materials, in last few years in Zhejiang, Shanghai, Jiangsu, Fujian, Hubei, Hunan and other provinces, municipalities directly under the central government have rapidder development. As the country did not develop unified product standards, Zhejiang, Shanghai, Jiangsu and some of the production plant to develop the industry standard, in the inspection of product quality, ensure the quality of construction project which played a positive role. But these standards in technical index, test methods are not unified, but also by the regional influence, hindering the new products to further promote the use of. Therefore, formulate a unified national concrete porous brick product standards, to improve the standards of accuracy, scientific, comparable, effectively control the quality of products, so as to ensure the quality of construction, advance steadily concrete porous brick to promote the use of great significance.
" Concrete porous brick" industry standard preparation plan issued, the standard drafting unit in 2002August the middle ten days of a month in Shanghai city to hold first meeting. Communicate on the meeting summed the concrete porous brick production, design, construction and experience, discuss and determine the standard content, arrange the work plan, established standards team. 2002August to October in Zhejiang, Shanghai and other places of product sampling test, product size deviation, appearance and other physical mechanical properties were measured. At the same time, the concrete porous brick production, use circumstance undertook investigation and study, put forward the Research Report and test report, formed a standard discussion draft. In 2002December in Zhejiang in the middle of Xiaoshan held a working meeting the second times, standards team is in the report on the meeting of the investigation and experimental verification of standard draft for discussion, put forward suggestions for amendments and supplements, and the arrangement of the second phase of the test verification work. On this foundation, put forward" standard compilation group of concrete porous brick" industry standard ( Draft for Soliciting Opinions ) and its compilation, sent to the relevant production enterprises, design and construction units, quality inspection, scientific research institutions and departments, extensive solicitation of opinions. In early March2003, in Zhejiang, Tonglu held a working meeting the third times, according to each district returns to the ideas, discuss, study, modified the standard draft, drafted the draft standard and relevant document, submitted in July 18, 2003examination meeting of standard. In the same month, according to the criteria for the validation of the authorized opinion, and other relevant departments and units of the written comments, Standard Establishment Subcommittee on the draft standard was revised, formed a draft. In April 15, 2004, China Building Materials Industry Association to invite relevant experts, and standards team together in the Beijing draft standard for approval of the final review final.
The standard main content as follows:
1 making the basis
According to the standards of production and practical use, reference the United States ASTM C55" concrete", and" GB8239ordinary concrete small hollow block"," GB13544sintered porous brick" and other national standards, based on the verification of experiment set.
2 standard name
Known as the" concrete porous brick", its main basis is, according to the GB / T 18968" terms of wall materials": (1) brick ( brick ): building with artificial small bulk. For rectangular hexahedral shape, there is also a variety of special-shaped. The length of not more than 365mm, the width of not more than240mm, height not exceeding115mm;
(2) Porous brick ( perforated brick ): void ratio is equal to or greater than 25%, the size of the holes is small and the number of bricks. Commonly used in the bearing part. The standard product specificationsDimensions are in the brick of defined size range, the void ratio of not less than 30%, the main raw material for cement and sand, hence the name " concrete porous brick".
3 terms and definitions
In order to regulate the concrete porous brick the names of parts, the standardUsing the diagram shown the way. Concrete porous brick parts of using GB / T 18968" term" standard of wall material.
4grade and mark
The 4.1 grade
According to the size deviation and appearance quality is divided into first class ( B ) and qualified products (C ); according to the intensity level is divided into MU10, MU15, MU20, MU25, MU30five intensity levels. According to the sample, the current production enterprise's product strength grade in MU7.5to MU20, used in building outer wall retaining structure ( including load-bearing and non-load-bearing ) and internal partition. Considering the current design, construction and acceptance, the enclosure wall provided by MU10, and the GB5101" fired common brick," GB 13544" sintered porous brick" all cancelled MU7.5, concrete porous brick for load-bearing structure and wall wall, in order to improve the service life of the building, the standard MU7.5 cancelled in.
Product name code with its English name first letters: CPB, so that the computer retrieval.
Concrete perforated bricks should adopt the provisions of GB175Portland cement and Portland cement, in order to obtain higher early strength and the corresponding strength grade, reduce the drying shrinkage. Slag Portland cement early strength is low, the natural curing condition, too many missing edge off angle will influence the appearance quality of the products; not using the volcano gray silicate cement, because its drying shrinkage is larger, maintenance and construction can cause improper brick cracks, affect the safe use of the building; the fly ash Portland cement, in the content of fly ash under the condition of large, products dry shrinkage ratio is larger, control is not good, can make the brick cracks, caused structural damage. Therefore, the requirements of this standard conforms to GB175Portland cement and Portland cement.
(2) the fine aggregate, coarse aggregate
Shall comply with GB / T14684 and GB / T14685 regulations: heavy slag shall comply with YBJ20584 regulations. The maximum size of coarse aggregate should not be greater than the minimum rib thickness. The appropriate amount of stone chips, can improve the compactness and strength of brick.
External mixing fly ash, this standard does not include. One reason: the product name for" concrete porous brick", the raw materials for the ordinary concrete, GB 8239" ordinary concrete small hollow block" are not involved with fly ash. This standard did not make the system studied previously, nor to beyond the range of. The two reasons : the fly ash not only relates to fly ash quality, but also relates to the range of dosage of fly ash, quality, quantity, number, on product quality affects the performance, standard should add some indicators, such as carbonation coefficient, softening coefficient, radioactive, and silicate products standards, beyond the scope of this standard. Therefore, if necessary, in the future should be developed to" fly ash brick" standard, otherwise resolved.
5.2pass structure(1) the standard notice rectangular holes on building energy efficiency," according to GB13544sintered porous brick", according to the existing provisions of the brick, concrete porous brick two pass set, a set of rectangular holes, a rectangular holes or other pass. In this article the rectangular holes baseline requirements.
(2) according to the standards of Zhejiang and Shanghai of concrete porous brick masonry and walls test data, from the architectural design can directly replace clay brick 's point of view, and pay attention to the characteristics of concrete materials, in order to prevent the products in the wall of the earthquake stress concentration point, provides the rectangular holes or rectangular bar hole4angle should be greater than 8mm fillet radius.
(3) according to the standards of Zhejiang and Shanghai of concrete porous brick masonry and walls test data, from the architectural design can directly substitute for clay brick angle consideration, set slurry paving surface should be half blind, and taking into account the masonry mortar shop requirements, set half blind hole circle diameter of not more than8mm.Production enterprises in the design to determine the shape and size of concrete porous brick, wall thickness, rib thickness, pore shape, pore rate, and product strength, strength of masonry, building thermal performance and other factors to consider.
5.3maintenance technology and siteThis standard pay attention to practical production products28d curing period on the product quality assurance role, especially for this provision.
6.1specificationsAccording to the standards of the wall brick with reference to GB 13544" basic module, sintered porous brick", and noted that the modulus brick dimensions and actual requirements, provides the concrete porous brick size.GB 13544" foreign" sintered porous brick wall thickness and rib thickness did not make a provision. This standard is based on the Zhejiang and Shanghai of perforated concrete brick and wall plate test set size, concrete porous brick wall thickness shall not be less than the minimum15mm, minimal rib thickness shall not be less than 10mm.Product size allowable deviation is divided into first class, qualified for the two grade, the index is higher than that of GB8239" ordinary concrete small hollow block" in quality, first-rate product, see Table 1Table 1Comparison of size deviation
6.2 the appearance qualityThis standard stipulated the appearance quality of the products is divided into first class and qualified products, its index is equivalent to GB 8239" ordinary concrete small hollow block" in the excellent products and first-class goods.6.3 holes are arrangedThis standard according to the existing building structure design on the product density requirements, regulations of concrete porous brick cavity ratio should be greater than or equal to 30%.This standard noticed rectangular holes on building energy efficiency," according to GB13544sintered porous brick", according to the existing provisions of the brick, concrete porous brick two pass set and a set of holes array, rectangular holes, a rectangular holes or other pass, and provision is made in the surface direction must have at least2 rows of holes.6.4gradeIn GB 8239" ordinary concrete small hollow block", ordinary concrete small hollow block strength grade of MU3.5, MU5.0, MU7.5, MU10.0, MU15.0and MU20.0; in GB / T 15229" lightweight aggregate concrete small hollow block", the lightweight aggregate concrete small hollow block strength grade : MU1.5, MU2.5, MU3.5, MU5.0, MU7.5and MU10.0; in GB 13544"" in sintered porous brick, sintered porous brick strength grade of MU30, MU25, MU20, MU15and MU10. These standards are in the low strength grade products used mainly for filling wall, retaining structure, thermal insulation; high strength grade products for bearing structure. This standard according to the actual production situation, and consider the future development, the strength of concrete perforated bricks grade is divided into MU10, MU15, MU20, MU25 and MU30 five grades, the strength grade of the average value of a single minimum value, according to the test data, and with reference to GB 8239" ordinary concrete small hollow brick" provisions are made for.6.5 drying shrinkage
Drying shrinkage index is a reflection of perforated concrete brick in temperature, humidity or changes in environmental conditions of their volumetric shrinkage deformation is an important index, product density, high water absorption, its drying shrinkage is sure to be. Concrete porous brick wall, due to the shrinkage deformation may cause the wall cracking, causes the wall to lose support or bearing structure function. Therefore, domestic and international product standards are made to this value. In the United States of America ASTM C55" concrete brick", set block dry shrinkage ratio should not be greater than 0.065%, in JC 862" fly ash small hollow block", drying shrinkage rate shall not be more than 0.06%; in the GB / T 15229" lightweight aggregate concrete small hollow block", drying shrinkage rate shall not should be greater than 0.065%. This standard is based on the Zhejiang and Shanghai areas of product sampling inspection data, from the architectural design can directly substitute for clay brick 's point of view, and pay attention to the characteristics of concrete materials, regulations of concrete porous brick drying shrinkage rate should be less than 0.045%.
6.6 relative water contentRelative moisture content is concrete porous brick factory on the moisture content and water absorption ratio. This indicator is for the control of masonry wall due to drying shrinkage cracks of wall products developed. The United States in the last century 30time already control block on the wall when the relative water content, Japanese standard also makes provision for. Table 2 lists the United States ASTM C55" concrete brick" of type I block relative moisture content provision, Japan in the JISA5406" concrete hollow block" stipulated in the relative moisture content should be less than 40%.
Table 2the United States of America ASTMC55concrete brick" relative"Moisture content of the request
Drying shrinkage rate ( % )
Maximum water rate of water absorption % (3on average)
The construction site or use of moisture conditions in D
The wet, dry, medium0.03 or less
Note: A an annual average relative humidity is greater than 75%The
B annual average relative humidity at 50% -75% between;The
C annual average relative humidity is less than 50%For the United States
D average relative humidity distribution of humidity conditions specified in theThe wall cracking, generally the people are from the housing stress and structural measures and other factors to analyze, and the United States of America research thinks, block relative moisture content is the main reason of wall cracking. Therefore, in order to ensure that the products manufactured with a moisture content on the wall when the moisture content is consistent, block production plant products manufactured in the general use of plastic bags. Our GB 8239" ordinary concrete small hollow block", on the block relative moisture content according to American ASTM C55drying shrinkage rate
" of 0.03% or less of a" made a provision. According to the standards of concrete porous brick drying shrinkage index, according to American ASTM C55" concrete brick" relative moisture content regulation, canceled the 0.045%-0.065% file.Production enterprises should be strictly in accordance with the provisions of this standard, control products factory of the relative moisture index, can reduce the concrete porous brick drying shrinkage cracking of wall, ensure the quality of masonry.
6.7frost resistanceFrost resistance concrete porous brick the durability index. This standard stipulated concrete perforated brick with Portland cement and Portland cement. The use of slag Portland cement and fly ash Portland cement, slag, slag, and fly ash mixed materials, will affect the durability of concrete porous brick. At the same time, some small enterprises adopt concrete porous brick brick forming quality is poorer, early maintenance is not good, not enough strength, may lead to concrete porous brick resistance drop. Therefore, the standard of non heating area and heating area are frost resistance test.
6.8impermeabilityProducts of impermeability and compactness are closely related. In order to ensure the construction quality, the standard for the external walls ( including drywall ) of concrete porous brick should be impermeability test.
6.9radioactiveBuilding materials radioactive indicators for national mandatory provisions. This standard stipulated concrete porous brick radioactive indicators should be in accordance with GB 6566" building materials radionuclide limits" requirements.
Concrete porous brick wall brick size based on rules, therefore, its size, appearance quality, hole arrangement and structure, wall thickness, rib thickness testing method, according to GB / T 2542" test methods for wall bricks" provisions. According to the test results, the standard porosity test test piece volume calculation should be accurate to 0.0001m3. Because GB / T2542" test methods for wall bricks" stipulated in the rectangular hole radius test method, the standard test using rectangle fillet radius 8mm standard examination board.
Concrete perforated brick material for ordinary concrete, the relevant technical requirements and GB 8293" ordinary concrete small hollow block" have same place, therefore, concrete porous brick strength, drying shrinkage, relative water content, frost resistance and impermeability test method based on GB / T 4111" small concrete hollow block test method for". As a result of concrete porous brick length is less than the normal concrete small hollow block, thus, the determination of drying shrinkage gauge for150mm; as a result of concrete porous brick wall thickness is less than normal concrete small hollow block, according to the test data, its impermeability test device of glass tube diameter specified for30mm. At the same time, as a result of GB / T 4111" test methods for the small concrete" is not on the test gauge makes a provision, the determination of the gauge.Concrete porous brick radioactive test according to GB 6566" building materials radionuclide limits" provisions.
Inspection lot size is dependent on the production of the production scale of enterprises, the two is the quality of enterprise management level. Company production scale, product quality and stability, then the inspection lot can be some big; conversely, the enterprise scale of production is minor, product quality fluctuation test batch should be smaller. Such inspection cost is high, but to bear product quality risk is also small in number. GB 13544" sintered porous brick" provisions of the inspection lot is 35000-150000for a number of less than 35000blocks, according to a number of gauge; GB 8239" ordinary concrete small hollow block" in10000as a batch, the monthly production of blocks is less than 10000pieces also by a number of gauge. This standard uses GB 13544"" provisions of sintered porous brick.
Sampling rules takes into account the current some small enterprises producing concrete perforated brick quality fluctuation, so the dimension deviation and appearance quality inspection sampling quantity according to GB 13544" sintered porous brick" provisions, in 50, strength grade is 10, the remaining test item sampling quantity according to the GB / T 4111" test methods for the small concrete" provisions. 50sample test sample after excess reserve.
Radioactive test sampling rules according to the GB 6566" building materials radionuclide limits" provisions.
9product certification, stacking and transport
China's concrete block factory general packaging, block on the wall when the moisture content with the delivery time, environmental conditions of temperature and humidity change, the block wall when the moisture content did not get due control, this is caused by the block wall crack. Control of concrete porous brick wall on the moisture content, to prevent concrete porous brick wall cracks has important role. The suggested standard of concrete porous brick factory, appropriate packaging.