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Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. According to the requirements of Notice on Printing Main technical contents of this standard: 1. General Provisions; 2. Terms and Symbols; 3. Basic Requirements; 4. Tests of Slump and Slump Loses through Time; 5. Test of Slump-flow and Slump-flow Loses through Time; 6. Test of Vebe Consistometer; 7. Test of Flow Time of Mixture from the Inverted Slump Cone; 8. Test of Passing Ability; 9. Test of Funnel; 10. Test of Slump-flow Time; 11. Test of Setting Time; 12. Test of Bleeding; 13. Test of Pressure Bleeding; 14. Test of Apparent Density; 15. Test of Air Content; 16. Test of Uniformity; 17. Test of Anti-segregating; 18. Test of Temperature; 19. Test of Adiabatic Temperature Rise. Main technical contents revised in this standard: 1. This standard is coordinated with relevant standards issued after 2002; 2. "Terms and Symbols" is added; 3. "Basic Requirements" is added as a chapter and mixture sampling, specimen preparation, test record, test report and the like are included in this chapter; 4. Methods for test of slump loses through time and slump-flow loses through time are added; 5. Method for test of slump is revised and perfected; 6. Method for test of slump-flow is revised and perfected; 7. Test of flow time of mixture from the inverted slump cone is added; 8. Method for test of passing ability is added; 9. Method for test of funnel is added; 10. Method for test of slump-flow time is added; 11. Method for test of pressure bleeding is revised and perfected; 12. Method for analysis test of mix ratio in the former standard is deleted; 13. Method for test of apparent density is revised and perfected; 14. Method for test of air content is revised and perfected; 15. Method for test of uniformity is added; 16. Method for test of anti-segregating is added; 17. Method for test of temperature is added; 18. Method for test of adiabatic temperature rise is added. The Ministry of Housing and Urban-Rural Development is in charge of the administration of this standard while China Academy of Building Research is responsible for the explanation of specific technical contents. During the process of implementing this standard, the relevant opinions and advice, whenever necessary, can be sent to China Academy of Building Research (Address: No.30 North 3rd Ring East Road, Beijing, 100013). Contents Foreword i 1 General Provisions 1 2 Terms and Symbols 1 2.1 Terms 1 2.2 Symbols 2 3 Basic Requirements 4 3.1 General Requirements 4 3.2 Sampling and Preparation of Specimen 4 4 Test of Slump and Slump Loses through Time 6 4.1 Test of Slump 6 4.2 Test of Slump Loses through Time 7 5 Test of Slump-flow and Slump-flow Loses through Time 8 5.1 Test of Slump-flow 8 5.2 Test of Slump-flow Loses through Time 9 6 Test of Vebe Consistometer 9 7 Test of Flow Time of Mixture from the Inverted Slump Cone 10 8 Test of Passing Ability 12 9 Test of Funnel 14 10 Test of Slump-flow Time 15 11 Test of Setting Time 16 12 Test of Bleeding 19 13 Test of Pressure Bleeding 22 14 Test of Apparent Density 24 15 Test of Air Content 26 16 Test of Uniformity 30 16.1 Mortar Density Method 30 16.2 Concrete Consistency Method 32 17 Test of Anti-segregating 34 18 Test of Temperature 35 19 Test of Adiabatic Temperature Rise 37 Annex A Test of Compacting Factor 40 Explanation of Wording in This Standard 44 List of Quoted Standards 45 1 General Provisions 1.0.1 This standard is formulated with a view to specifying and unifying the test method of performance on ordinary fresh concrete, enhancing the level of testing technique, ensuring the performance on fresh concrete, and meeting the quality requirement for precast concrete member and cast-in-place concrete work. 1.0.2 This standard is applicable to the test of performance on ordinary fresh concrete. 1.0.3 Test of performance on ordinary fresh concrete shall not only comply with the provisions of this standard, but also those specified in the relevant current ones of the nation. 2 Terms and Symbols 2.1 Terms 2.1.1 ordinary concrete concrete with dry apparent density of 2,000kg/m3~2,800kg/m3 2.1.2 slump the slumped height of fresh concrete under the action of deadweight 2.1.3 slump-flow the extended diameter of fresh concrete after slumping 2.1.4 passing ability the performance of fresh concrete in uniformly passing through gap 2.1.5 J-Ring annular instrument used for determining the passing ability of fresh concrete 2.1.6 self-compacting concrete the concrete with high fluidity, uniformity and stability and capable of flowing and filling the space of formwork under the action of deadweight without tamping by external force during pouring 2.1.7 slump-flow time the time required for fresh concrete to expand to the diameter of 500mm after slumping 2.1.8 bleeding the phenomenon of fresh concrete in bleeding moisture content 2.1.9 pressure bleeding the bleeding phenomenon of fresh concrete under pressure effect 2.1.10 consistency index characterizing the flowability of fresh concrete, which can be represented by slump, Vebe consistency or slump-flow 2.1.11 segregation resistance performance of all kinds of components in the fresh concrete for maintaining homogeneous dispersion 2.1.12 adiabatic temperature rise temperature rise of concrete caused by hydration of cementing material under adiabatic condition 2.2 Symbols 2.2.1 Slump Ho——the initial slump value of fresh concrete when it comes out from mixer; H60——the slump value of fresh concrete after standing for 60min. 2.2.2 Slump-flow L0——the initial slump-flow value of fresh concrete when it comes out from mixer; L60——the slump-flow value of fresh concrete after standing for 60min. 2.2.3 Flow time tsf,m——the average value of the flow time of fresh concrete from the inverted slump cone measured in two tests; tsf1,tsf2——the flow time of fresh concrete from the inverted slump cone measured in two tests respectively. 2.2.4 Bleeding amount Ba——the bleeding amount of fresh concrete in unit area; V10——the bleeding amount when pressurizing for 10s; V140——the bleeding amount when pressurizing for 140s. 2.2.5 Bleeding rate B——the bleeding rate; BV——the pressure bleeding rate. 2.2.6 Air content A——the air content of fresh concrete; A0——the air content of uncorrected fresh concrete; Ag——the air content of aggregate. 2.2.7 Density ρ——the apparent density of fresh concrete; ρw——the water density; ρm——the apparent density of concrete mortar mixture; ρmax——the larger apparent density of concrete mortar mixture sampled from that first and last coming out of the mixer; Δρm——the difference of apparent densities of concrete mortar mixture sampled from that first and last coming out of the mixer. 2.2.8 Others DRρ——the deviation rate of concrete mortar density; SR——the separation rate of fresh concrete; fPR——the penetration resistance in unit area; α——the correction coefficient of adiabatic temperature rise for test equipment; θn——the adiabatic temperature rise value of concrete of n days in age; θ′n——the temperature rise value of concrete of n days in age recorded by instrument; θ0——the initial temperature of fresh concrete. 3 Basic Requirements 3.1 General Requirements 3.1.1 The maximum nominal particle size of aggregate shall meet the relevant requirements of the current professional standard JGJ 52 Standard for Technical Requirements and Test Method of Sand and Crushed Stone (or Gravel) for Ordinary Concrete. 3.1.2 Relative humidity of test environment should not be less than 50% and the temperature shall be maintained at 20℃±5℃; the temperature of adopted material, test equipment, container and auxiliary equipment should keep consistent with the test room temperature. 3.1.3 If the test is carried out on site, concrete specimen shall be free from the influence of wind, rain, snow and direct sunlight. 3.1.4 When specimen is prepared for fresh concrete performance test, the adopted mixer shall meet the requirements of the current professional standard JG 244 Mixers for Concrete Test. 3.1.5 The test equipment shall be calibrated prior to use. 3.2 Sampling and Preparation of Specimen 3.2.1 As for the sampling of fresh concrete of the same group, samples shall be taken from the concrete on the same pan or same vehicle. The sampling amount shall be more than 1.5 times of the required amount, and should not be less than 20L. 3.2.2 Representative samples of fresh concrete shall be taken by the method of sampling for many times. Samples should be taken at 1/4, 1/2 and 3/4 of concrete on the same pan or same vehicle respectively, and mixed uniformly; the time interval between the first sampling and the last sampling should not exceed 15min. 3.2.3 Performance test should be carried out within 5min after sampling. 3.2.4 The mixing of the fresh concrete prepared in test room shall meet the following requirements: 1 Mixer shall be adopted for mixing the fresh concrete. Prior to mix, the mixer is washed out, a small amount of the same fresh concrete or mortar of same water-binder ratio is premixed, and the residual material shall be unloaded after back mortaring; 2 The weighted coarse aggregate, cementing material, fine aggregate and water shall be put into mixer successively; indissolvable and insoluble powdery admixture should be put into mixer together with cementing material; liquid and soluble admixture should be put into mixer together with mixing water; 3 Fresh concrete should be mixed for more than 2min until it becomes uniform; 4 The amount of fresh concrete in one mixing should not be less than 1/4 of the nominal capacity of mixer, shall not be greater than the nominal capacity of mixer and shall not be less than 20L. 3.2.5 When mixing concrete in test room, the material consumption shall be counted by mass. Weighing accuracy of aggregate shall be ±0.5%; the weighing accuracy of cement, additive, water and admixture shall be ±0.2%. 3.2.6 When sampling, the following contents shall be recorded or written in the test or inspection report: 1 Sampling date, time and person; 2 Project name and structure position; 3 Concrete watering time and mixing time; 4 Concrete mark; 5 Sampling method; 6 Specimen number; 7 Specimen quantity; 8 Environment temperature and weather condition during sampling. 9 Temperature of sampled concrete. 3.2.7 When preparing fresh concrete in test room, besides the contents required in 3.2.6, the following contents shall be recorded and written in test or test report; 1 Test environment temperature; 2 Test environment humidity; 3 Variety, specification, origin of production and performance index of all kinds of raw materials; 4 Concrete mix ratio and material consumption of concrete in each pan. 4 Test of Slump and Slump Loses through Time 4.1 Test of Slump 4.1.1 This test method should be used to determine the slump of the fresh concrete with maximum nominal particle size of aggregate not greater than 40mm and the slump not less than 10mm. 4.1.2 The equipment for test of slump shall meet the following requirements: 1 Apparatus for concrete slump test shall meet the requirements of the current professional standard JG/T 248 Apparatus for Concrete Slump Test; 2 Two steel rulers shall be equipped and the measuring range of steel ruler shall not be less than 300mm, and the division value shall not be larger than 1mm. 3 Steel plates with plane size not less than 1,500mm×1,500mm, thickness not less than 3mm and maximum deflection not greater than 3mm shall be adopted as bottom plates. 4.1.3 The test of slump shall be carried out according to the following procedures: 1 The inner wall and bottom plate of slump cone shall be moist and without visible water. Put the bottom plate on solid horizontal plane and put the slump cone at the center of the bottom plate, then stamp on the pedals of both sides; keep the slump cone at the same position when feeding; 2 Fresh concrete specimen shall be put into slump cone uniformly by three layers; after each layer of fresh concrete is put, it shall be tamped with tamping rod for 25 times uniformly from edge to center in spiral shape; after tamping, the height of each layer of fresh concrete specimen shall be 1/3 of the height of cone. 3 When the bottom layer is tamped, the tamping rod shall run through the whole depth, when the second layer and the top layer are tamped, the tamping rod shall run through this layer to the surface of next layer; 4 The fresh concrete at top layer shall be higher than the opening of cone, in the process of tamping, if the fresh concrete is lower than the opening, fresh concrete shall be added at any time. 5 After tamping the top layer, take down the feed hopper, scrape off the excessive fresh concrete and trowell the fresh concrete along the opening. 6 After removing the concrete on the bottom plate of cone side, the slump cone shall be lifted vertically and steadily and put near the specimen carefully; when the specimen stops slumping or the slump time is up to 30s, the difference between cone height and the highest point of slumping concrete specimen shall be measured with steel ruler to serve as the slump value of fresh concrete. 4.1.4 The lifting process of slump cone should be controlled in 3s~7s; the whole process from feeding to lifting slump cone shall be carried out continuously and shall be completed within 150s. 4.1.5 After lifting the slump cone, if collapse or shear failure occurs at one side of concrete, sample shall be retaken for determination; if collapse or shear failure occurs again at one side of concrete in the second test, it shall be recorded and described. 4.1.6 The measurement of slump value of fresh concrete shall be to the nearest 1mm and the result shall be rounded off to 5mm. 4.2 Test of Slump Loses through Time 4.2.1 This test method may be used to determine the variant of slump of fresh concrete along with the standing time. 4.2.2 The equipment for test of slump loses through time shall meet the requirements in 4.1.2. 4.2.3 The test of slump loses through time shall be conducted according to the following procedures: 1 The initial slump value H0 of fresh concrete flowing out from the mixer shall be measured; 2 Put all the fresh concrete specimen in plastic drum or metal drum not corroded by cement paste, and seal with drum cover or plastic film and keep it still. 3 Start timing from adding water in mixing, keep it still for 60min and pour all the fresh concrete specimen in drum into mixer and mix for 20s, then subject it to slump test to obtain the slump value H60 in at 60min. 4 Calculate the difference between initial slump value and slump value at 60min to obtain the test result of concrete slump loses through time of 60min. 4.2.4 If the engineering requires to adjust the time for keeping still, the concrete slump loses through time shall be determined and calculated according to the actual time for keeping still. Foreword i 1 General Provisions 2 Terms and Symbols 2.1 Terms 2.2 Symbols 3 Basic Requirements 3.1 General Requirements 3.2 Sampling and Preparation of Specimen 4 Test of Slump and Slump Loses through Time 4.1 Test of Slump 4.2 Test of Slump Loses through Time 5 Test of Slump-flow and Slump-flow Loses through Time 5.1 Test of Slump-flow 5.2 Test of Slump-flow Loses through Time 6 Test of Vebe Consistometer 7 Test of Flow Time of Mixture from the Inverted Slump Cone 8 Test of Passing Ability 9 Test of Funnel 10 Test of Slump-flow Time 11 Test of Setting Time 12 Test of Bleeding 13 Test of Pressure Bleeding 14 Test of Apparent Density 15 Test of Air Content 16 Test of Uniformity 16.1 Mortar Density Method 16.2 Concrete Consistency Method 17 Test of Anti-segregating 18 Test of Temperature 19 Test of Adiabatic Temperature Rise Annex A Test of Compacting Factor Explanation of Wording in This Standard List of Quoted Standards 1 总 则 1.0.1 为规范和统一普通混凝土拌合物性能试验方法,提高试验技术水平,保证混凝土拌合物性能,满足预制混凝土构件和现浇混凝土工程的质量要求,制定本标准。 1.0.2本标准适用于普通混凝土拌合物性能的试验。 1.0.3普通混凝土拌合物性能试验除应符合本标准的规定外,尚应符合国家现行有关标准的规定。 2术语和符号 2.1 术 语 2.1.1普通混凝土ordinary concrete 干表观密度为2000kg/m3~2800kg/m3的混凝土。 2.1.2坍落度slump 混凝土拌合物在自重作用下坍落的高度。 2.1.3扩展度slump-flow 混凝土拌合物坍落后扩展的商径。 2.1.4间隙通过性passing ability 混凝土拌合物均匀通过间隙的性能。 2.1.5 J环 J-Ring 测定混凝土拌合物间隙通过性的环形仪器。 2.1.6 自密实混凝土self-compacling concrete 具有高流动性、均匀性和稳定性,浇筑时无需外力振捣,能够在自重作用下流动并充满模板空间的混凝土。 2.1.7扩展时间 slump-flow time 混凝土拌合物坍落后扩展直径达到500mm所需的时间。 2.1.8泌水bleeding 混凝土拌合物析出水分的现象。 2.1.9压力泌水pressure bleeding 混凝土拌合物在压力作用下的泌水现象。 2.1.10 稠度 consistency 表征混凝土拌合物流动性的指标,可用坍落度、维勃稠度或扩展度表示。 2.1.11抗离析性segregation resistance 混凝土拌合物中各种组分保持均匀分散的性能。 2.1.12 绝热温升 adiabatic temperature rise 混凝土在绝热状态下,由胶凝材料水化导致的温度升高。 2.2符 号 2.2.1坍落度 HD——出机时的混凝土拌合物的初始坍落度值; H60——混凝土拌合物静置60min后的坍落度值。 2.2.2扩展度 L0——出机时的混凝土拌合物的初始扩展度值; L60——混凝土拌合物静置60min后的扩展度值。 2.2.3排空时间 tsf,m——两次试验测得的倒置坍落度筒中混凝土拌合物排空时间的平均值; tsf1,tsf2——两次试验分别测得的倒置坍落度筒中混凝土拌合物排空时间。 2.2.4泌水量 Ba——单位面积混凝土拌合物的泌水量; V10——加压至10s时的泌水量; V140——加压至140s时的泌水量。 2.2.5泌水率 B——泌水率; BV——压力泌水率。 2.2.6含气量 A——混凝土拌合物含气量; A0——未校正的混凝土拌合物的含气量; Ag——骨料的含气量。 2.2.7密度 ρ——混凝土拌合物表观密度; ρw——水的密度; ρm——混凝土砂浆拌合物的表观密度; ρmax——先后出机取样混凝土砂浆拌合物表观密度的大值; Δρm——先后出机取样混凝土砂浆拌合物表观密度的差值。 2.2.8其他 DRρ——混凝土砂浆密度偏差率; SR——混凝土拌合物离析率; fPR——单位面积贯入阻力; α——试验设备绝热温升修正系数; θn——n天龄期混凝土的绝热温升值; θ′n——n天龄期仪器记录的温升值; θ0——混凝土拌合物的初始温度。 3基本规定 3.1 一般规定 3.1.1骨料最大公称粒径应符合现行行业标准《普通混凝土用砂、石质量及检验方法标准》JGJ 52的规定。 3.1.2试验环境相对湿度不宜小于50%,温度应保持在20℃±5℃;所用材料、试验设备、容器及辅助设备的温度宜与试验室温度保持一致。 3.1.3现场试验时,应避免混凝土拌合物试样受到风、雨雪及阳光直射的影响。 3.1.4制作混凝土拌合物性能试验用试样时,所采用的搅拌机应符合现行行业标准《混凝土试验用搅拌机》JG 244的规定。 3.1.5试验设备使用前应经过校准。 3.2取样与试样的制备 3.2.1 同一组混凝土拌合物的取样,应在同一盘混凝土或同一车混凝土中取样。取样量应多于试验所需量的1.5倍,且不宜小于20L。 3.2.2混凝土拌合物的取样应具有代表性,宜采用多次采样的方法。宜在同一盘混凝土或同一车混凝土中的1/4处、1/2处和3/4处分别取样,并搅拌均匀;第一次取样和最后一次取样的时间间隔不宜超过15min。 3.2.3宜在取样后5min内开始各项性能试验。 3.2.4试验室制备混凝土拌合物的搅拌应符合下列规定: 1 混凝土拌合物应采用搅拌机搅拌,搅拌前应将搅拌机冲洗干净,并预拌少量同种混凝土拌合物或水胶比相同的砂浆,搅拌机内壁挂浆后将剩余料卸出; 2称好的粗骨料、胶凝材料、细骨料和水应依次加入搅拌机,难溶和不溶的粉状外加剂宜与胶凝材料同时加入搅拌机,液体和可溶外加剂宜与拌合水同时加入搅拌机; 3 混凝土拌合物宜搅拌2min以上,直至搅拌均匀; 4混凝土拌合物一次搅拌量不宜少于搅拌机公称容量的1/4,不应大于搅拌机公称容量,且不应少于20L。 3.2.5试验室搅拌混凝土时,材料用量应以质量计。骨料的称量精度应为±0.5%:水泥、掺合料、水、外加剂的称量精度均应为±0.2%。 3.2.6取样应记录下列内容并写入试验或检测报告: 1取样日期、时间和取样人; 2工程名称、结构部位; 3混凝土加水时间和搅拌时间; 4混凝土标记; 5取样方法; 6试样编号; 7试样数量; 8环境温度及取样的天气情况; 9取样混凝土的温度。 3.2.7在试验室制备混凝土拌合物时,除本标准第3.2.6条规定的内容外,尚应记录下列内容并写入试验或检测报告: 1试验环境温度; 2试验环境湿度; 3各种原材料品种、规格、产地及性能指标; 4混凝土配合比和每盘混凝土的材料用量。 4坍落度试验及坍落度经时损失试验 4.1坍落度试验 4.1.1 本试验方法宜用于骨料最大公称粒径不大于40mm、坍落度不小于10mm的混凝土拌合物坍落度的测定。 4.1.2坍落度试验的试验设备应符合下列规定: 1坍落度仪应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定; 2应配备2把钢尺,钢尺的量程不应小于300mm,分度值不应大于1 mm; 3底板应采用平面尺寸不小于1500mm×1500mm、厚度不小于3mm的钢板,其最大挠度不应大于3mm。 4.1.3坍落度试验应按下列步骤进行: 1坍落度筒内壁和底板应润湿无明水;底板应放置在坚实水平面上,并把坍落度筒放在底板中心.然后用脚踩住两边的脚踏板,坍落度筒在装料时应保持在同定的位置; 2混凝土拌合物试样应分三层均匀地装入坍落度筒内,每装一层混凝土拌合物,应用捣棒由边缘到中心按螺旋形均匀插捣25次,捣实后每层混凝土拌合物试样高度约为筒高的三分之一; 3插捣底层时,捣棒应贯穿整个深度,插捣第二层和顶层时,捣棒应插透本层至下一层的表面; 4顶层混凝土拌合物装料应高出筒口,捅捣过程中,混凝土拌合物低于筒口时,应随时添加; 5顶层插捣完后,取下装料漏斗,应将多余混凝土拌合物刮去,并沿筒口抹平; 6清除筒边底板上的混凝土后,应垂直平稳地提起坍落度筒,并轻放于试样旁边;当试样不再继续坍落或坍落时间达30s时,用钢尺测量出筒高与坍落后混凝土试体最高点之间的高度差,作为该混凝土拌合物的坍落度值。 4.1.4坍落度筒的提离过程宜控制在3s~7s;从开始装料到提坍落度筒的整个过程应连续进行,并应在150s内完成。 4.1.5将坍落度筒提起后混凝土发生一边崩坍或剪坏现象时,应重新取样另行测定;第二次试验仍出现一边崩坍或剪坏现象,应予记录说明。 4.1.6混凝土拌合物坍落度值测量应精确至1mm,结果应修约军5mm。 4.2坍落度经时损失试验 4.2.1 本试验方法可用于混凝土拌合物的坍落度随静置时间变化的测定。 4.2.2坍落度经时损失试验的试验设备应符合本标准第4.1.2条的规定。 4.2.3坍落度经时损失试验应按下列步骤进行: 1 应测量出机时的混凝土拌合物的初始坍落度值H0; 2将全部混凝土拌合物试样装入塑料桶或不被水泥浆腐蚀的金属桶内,应用桶盖或塑料薄膜密封静置; 3 自搅拌加水开始计时,静置60min后应将桶内混凝土拌合物试样全部倒入搅拌机内,搅拌20s,进行坍落度试验,得出60min坍落度值H60; 4计算初始坍落度值与60min坍落度值的差值,可得到60min混凝土坍落度经时损失试验结果。 4.2.4当工程要求调整静置时间时,则应按实际静置时间测定并计算混凝土坍落度经时损失。 5扩展度试验及扩展度经时损失试验 5.1扩展度试验 5.1.1本试验方法宜用于骨料最大公称粒径不大于40mm、坍落度不小于160mm混凝土扩展度的测定。 5.1.2扩展度试验的试验设备应符合下列规定: 1坍落度仪应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定; 2钢尺的量程不应小于1000mm,分度值不应大于1mm; 3底板应采用平面尺寸不小于1500mm×1500mm、厚度不小于3mm的钢板,其最大挠度不应大于3mm。 5.1.3扩展度试验应按下列步骤进行: 1试验设备准备、混凝土拌合物装料和插捣应符合本标准第4.1.3条中第1~5款的规定; 2清除筒边底板上的混凝土后,应垂直平稳地提起坍落度筒,坍落度筒的提离过程宜控制在3s~7s;当混凝土拌合物不再扩散或扩散持续时间已达50s时,应使用钢尺测量混凝土拌合物展开扩展面的最大直径以及与最大直径呈垂直方向的直径; 3 当两直径之差小于50mm时,应取其算术平均值作为扩展度试验结果;当两直径之差不小于50mm时,应重新取样另行测定。 5.1.4发现粗骨料在中央堆集或边缘有浆体析出时,应记录说明。 5.1.5扩展度试验从开始装料到测得混凝土扩展度值的整个过程应连续进行,并应在4min内完成。 5.1.6混凝土拌合物扩展度值测量应精确至1mm,结果修约至5mm。 5.2扩展度经时损失试验 5.2.1本试验方法可用于混凝土拌合物的扩展度随静置时间变化的测定。 5.2.2扩展度经时损失试验的试验设备应符合本标准第5.1.2条的规定。 5.2.3扩展度经时损失试验应按下列步骤进行: 1应测量出机时的混凝土拌合物的初始扩展度值L0; 2将全部混凝土拌合物试样装入塑料桶或不被水泥浆腐蚀的金属桶内,应用桶盖或塑料薄膜密封静置; 3 自搅拌加水开始计时,静置60min后应将桶内混凝土拌合物试样全部倒入搅拌机内,搅拌20s,即进行扩展度试验,得出60min扩展度值L60; 4计算初始扩展度值与60min扩展度值的差值.可得到60min混凝土扩展度经时损失试验结果。 5.2.4 当工程要求调整静置时间时,则应按实际静置时间测定并计算混凝土扩展度经时损失。 6维勃稠度试验 6.0.1 本试验方法宜用于骨料最大公称粒径不大于40mm,维勃稠度在5s~30s的混凝土拌合物维勃稠度的测定;坍落度不大于50mm或干硬性混凝土和维勃稠度大于30s的特干硬性混凝土拌合物的稠度,可采用本标准附录A增实因数法进行测定。 6.0.2维勃稠度试验的试验设备应符合下列规定: 1维勃稠度仪应符合现行行业标准《维勃稠度仪》JG/T 250的规定; 2秒表的精度不应低于0.1s。 6.0.3试验应按下列步骤进行: 1 维勃稠度仪应放置在坚实水平面上,容器、坍落度筒内壁及其他用具应润湿无明水。 2喂料斗应提到坍落度筒上方扣紧,校正容器位置,应使其中心与喂料中心重合,然后拧紧嘲定螺钉。 3混凝土拌合物试样应分三层均匀地装入坍落度筒内,捣实后每层高度应约为筒高的三分之一。每装一层,应用捣棒在筒内由边缘到中心按螺旋形均匀插捣25次;插捣底层时,捣棒应贯穿整个深度,插捣第二层和顶层时,捣棒应插透本层至下一层的表面;顶层混凝土装料应高出筒口,插捣过程中,混凝土低于筒口,应随时添加。 4顶层插捣完应将喂料斗转离,沿坍落度筒口刮平顶面,垂直地提起坍落度筒,不应使混凝土拌合物试样产生横向的扭动。 5将透明圆盘转到混凝土圆台体顶面,放松测杆螺钉,应使透明圆盘转至混凝土锥体上部,并下降至与混凝土顶面接触。 6拧紧定位螺钉,开启振动台,同时用秒表计时,当振动到透明圆盘的整个底面与水泥浆接触时应停止计时,并关闭振动台。 6.0.4秒表记录的时间应作为混凝土拌合物的维勃稠度值,精确至1s。 7倒置坍落度筒排空试验 7.0.1本试验方法可用于倒置坍落度筒中混凝土拌合物排空时间的测定。 7.0.2倒置坍落度筒排空试验的试验设备应符合下列规定: 1 倒置坍落度筒的材料、形状和尺寸应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定,小口端应设置可快速开启的密封盖; 2底板应采用平面尺寸不小于1500mm×1500mm、厚度不小于3mm的钢板,其最大挠度不应大于3mm; 3支撑倒置坍落度筒的台架应能承受装填混凝土和插捣,当倒置坍落度筒放于台架上时,其小口端距底板不应小于500mm,且坍落度筒中轴线应垂直于底板; 4捣棒应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定; 5秒表的精度不应低于0.01s。 7.0.3倒置坍落度筒排空试验应按下列步骤进行: 1将倒置坍落度筒支撑在台架上,应使其中轴线垂直于底板,筒内壁应湿润无明水,关闭密封盖。 2混凝土拌合物应分两层装入坍落度筒内,每层捣实后高度宜为筒高的1/2。每层用捣棒沿螺旋方向由外向中心插捣15次,插捣应在横截面上均匀分布,插捣筒边混凝土时,捣棒可以稍稍倾斜。插捣第一层时,捣棒应贯穿混凝土拌合物整个深度;插捣第二层时,捣棒宜插透到第一层表面下50mm。插捣完应刮去多余的混凝土拌合物,用抹刀抹平。 3打开密封盖,用秒表测量自开盖至坍落度筒内混凝土拌合物全部排空的时间tsf,精确至0.01s。从开始装料到打开密封盖的整个过程应在150s内完成。 7.0.4宜在5min内完成两次试验,并应取两次试验测得排空时间的平均值作为试验结果,计算应精确至0.1s。 7.0.5 倒置坍落度筒排空试验结果应符合下式规定: |tsf1-tsf2|≤0.05tsf,m (7.0.5) 式中:tsf,m——两次试验测得的倒置坍落度筒中混凝土拌合物排空时间的平均值(s); tsf1,tsf2——两次试验分别测得的倒置坍落度筒中混凝土拌合物排空时间(s)。 8间隙通过性试验 8.0.1 本试验方法宜用于骨料最大公称粒径不大于20mm的混凝土拌合物间隙通过性的测定。 8.0.2混凝土拌合物间隙通过性试验的试验设备应符合下列规定: 1 J环应由钢或不锈钢制成,圆环中心直径应为300mm,厚度应为25mm;并应用螺母和垫圈将16根圆钢锁在圆环上,圆钢直径应为16mm,高应为100mm;圆钢中心间距应为58.9mm(图8.0.2); 2混凝土坍落度筒不应带有脚踏板.材料和尺寸应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定; 图8.0.2 J环示意图(mm) 3底板应采用平面尺寸不小于1500mm×1500mm、厚度不小于3mm的钢板,其最大挠度不应大于3mm。 8.0.3混凝土拌合物的间隙通过性试验应按下列步骤进行: 1底板、J环和坍落度筒内壁应润湿无明水;底板应放置在坚实的水平面上,J环应放在底板中心; 2坍落度筒应正向放置在底板中心,应与J环同心,将混凝土拌合物一次性填充至满; 3用刮刀刮除坍落度筒顶部混凝土拌合物余料,应将混凝土拌合物沿坍落度筒口抹平;清除筒边底板上的混凝土后,应垂直平稳地向上提起坍落度筒至250mm±50mm高度,提离时间宜控制在3s~7s;自开始入料至提起坍落度筒应在150s内完成;当混凝土拌合物不再扩散或扩散持续时间已达50s时,测量展开扩展面的最大直径以及与最大直径呈垂直方向的直径;测量应精确至1mm,结果修约至5mm。 8.0.4 J环扩展度应为混凝土拌合物坍落扩展终止后扩展面相互垂直的两个直径的平均值,当两直径之差大于50mm时,应重新试验测定。 8.0.5混凝土扩展度与J环扩展度的差值应作为混凝土间隙通过性性能指标结果。 8.0.6骨料在J环圆钢处出现堵塞时,应予记录说明。 9漏斗试验 9.0.1本试验方法宜用于骨料最大公称粒径不大于20mm的混凝土拌合物稠度和填充性的测定。 9.0.2漏斗试验的试验设备应符合下列规定: 1漏斗应由厚度不小于2mm钢板制成,漏斗的内表面应经过加工;在漏斗出料口的部位,应附设快速开启的密封盖(图9.0.2): 图9.0.2漏斗示意图(mm) 1—可活动的密封盖 2—底板应采用平面尺寸不小于1500mm×1500mm、厚度不小于3mm的钢板,其最大挠度不应大于3mm; 3支承漏斗的台架宜有调整装置,应确保台架的水平,漏斗支撑在台架上时,其中轴线应垂直于底板;台架应能承受装填混凝土,且易于搬运; 4盛料容器容积不应小于12L; 5秒表精度不应低于0.1s。 9.0.3漏斗试验应按下列步骤进行: 1将漏斗稳同于台架上,应使其上口呈水平,本体为垂直;漏斗内壁应润湿无明水,关闭密封盖; 2应用盛料容器将混凝土拌合物由漏斗的上口平稳地一次性填入漏斗至满;装料整个过程不应搅拌和振捣,应用刮刀沿漏斗上口将混凝土拌合物试样的顶面刮平; 3在出料口下方应放置盛料容器;漏斗装满试样静置10s±2s,应将漏斗出料口的密封盖打开,用秒表测量自开盖至漏斗内混凝土拌合物全部流出的时间。 9.0.4宜在5min内完成两次试验,应以两次试验混凝土拌合物全部流出时间的算术平均值作为漏斗试验结果,结果应精确至0.1s。 9.0.5混凝土拌合物从漏斗中应连续流出;混凝土出现堵塞状况,应重新试验;再次出现堵塞情况,应记录说明。 10扩展时间试验 10.0.1本试验方法可用于混凝土拌合物稠度和填充性的测定。 10.0.2扩展时间试验的试验没备应符合下列规定: 1 混凝土坍落度仪应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定; 2底板应采用平面尺寸不小于1000mm×1000mm、最大挠度不大于3mm的钢板,并应在平板表面标出坍落度筒的中心位置和直径分别为200mm、300mm、500mm、600mm、700mm、800mm及900mm的同心圆(图10.0.2); 图10.0.2底板(mm) 3盛料容器不应小于8L,并易于向坍落度筒装填混凝土拌合物; 4秒表精度不应低于0.1s。 10.0.3扩展时间试验应按下列步骤进行: 1底板应放置在坚实的水平面上,底板和坍落度筒内壁应润湿无明水,坍落度筒应放在底板中心,并在装料时应保持在同定的位置; 2应用盛料容器一次性将混凝土拌合物均匀填满坍落度筒,且不得捣实或振动;自开始入料至填充结束应控制在40s以内; 3取下装料漏斗,应将混凝土拌合物沿坍落度筒口抹平;清除筒边底板上的混凝土拌合物后,应垂直平稳地提起坍落度筒至250mm±50mm高度,提起时间宜控制在3s~7s; 4测定扩展时间时,应自坍落度筒提离地面时开始,至扩展开的混凝土拌合物外缘初触平板上所绘直径500mm的圆周为止,结果精确至0.1s。 11凝结时间试验 11.0.1 本试验方法宜用于从混凝土拌合物中筛出砂浆用贯入阻力法测定坍落度值不为零的混凝土拌合物的初凝时间与终凝时间。 11.0.2凝结时间试验的试验设备应符合下列规定: 1贯入阻力仪的最大测量值不应小于1000N,精度应为±10N;测针长100mm,在距贯入端25mm处应有明显标记;测针的承压面积应为100mm2、50mm2和20mm2三种; 2砂浆试样筒应为上口内径160mm,下口内径150mm,净高150mm刚性不透水的金属圆筒,并配有盖子; 3试验筛应为筛孔公称直径为5.00mm的方孔筛,并应符合现行国家标准《试验筛技术要求和检验 第2部分:金属穿孔板试验筛》GB/T 6003.2的规定; 4振动台应符合现行行业标准《混凝土试验用振动台》JG/T 245的规定; 5捣棒应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定。 11.0.3混凝土拌合物的凝结时间试验应按下列步骤进行: 1应用试验筛从混凝土拌合物中筛出砂浆,然后将筛出的砂浆搅拌均匀;将砂浆一次分别装入二三个试样筒中。取样混凝土坍落度不大于90mm时,宜用振动台振实砂浆;取样混凝土坍落度大于90mm时,宜用捣棒人工捣实。用振动台振实砂浆时。振动应持续到表面出浆为止。不得过振;用捣棒人工捣实时,应沿螺旋方向由外向中心均匀插捣25次,然后用橡皮锤敲击筒壁,直至表面插捣孔消失为止。振实或插捣后,砂浆表面宜低于砂浆试样筒口10mm,并应立即加盖。 2砂浆试样制备完毕,应置于温度为20℃±2℃的环境中待测,并在整个测试过程中,环境温度应始终保持20℃±2℃。在整个测试过程中,除在吸取泌水或进行贯入试验外,试样筒应始终加盖。现场同条件测试时,试验环境应与现场一致。 3凝结时间测定从混凝土搅拌加水开始计时。根据混凝土拌合物的性能,确定测针试验时间,以后每隔0.5h测试一次,在临近初凝和终凝时,应缩短测试间隔时间。 4在每次测试前2min,将一片20mm±5mm厚的垫块垫入筒底一侧使其倾斜.用吸液管吸去表面的泌水,吸水后应复原。 5测试时,将砂浆试样筒置于贯入阻力仪上,测针端部与砂浆表面接触,应在10s±2s内均匀地使测针贯入砂浆25mm±2mm深度,记录最大贯入阻力值,精确至10N;记录测试时间,精确至1min。 6每个砂浆筒每次测1个~2个点,各测点的间距不应小于15mm,测点与试样筒壁的距离不应小于25mm。 7每个试样的贯入阻力测试不应少于6次,直至单位面积贯入阻力大于28MPa为止。 8根据砂浆凝结状况,在测试过程中应以测针承压面积从大到小顺序更换测针,更换测针应按表11.0.3的规定选用。 表11.0.3测针选用规定表 单位面积贯入阻力 (MPa) 0.2~3.5 3.5~20 20~28 测针面积(mm2) 100 50 20 11.0.4 单位面积贯入阻力的结果计算以及初凝时间和终凝时间的确定应按下列方法进行: 1单位面积贯入阻力应按下式计算: (11.0.4-1) 式中:fPR——单位面积贯入阻力(MPa),精确至0.1MPa; P——贯入阻力(N); A——测针面积(mm2)。 2凝结时间宜按式(11.0.4-2)通过线性回归方法确定;根据式(11.0.4-2)可求得当单位面积贯入阻力为3.5MPa时对应的时间应为初凝时间,单位面积贯入阻力为28MPa时对应的时间应为终凝时间。 Int=a+blnfPR (11.0.4-2) 式中:t——单位面积贯入阻力对应的测试时间(min); a、b——线性回归系数。 3凝结时间也可用绘图拟合方法确定,应以单位面积贯入阻力为纵坐标,测试时间为横坐标,绘制出单位面积贯入阻力与测试时间之间的关系曲线;分别以3.5MPa和28MPa绘制两条平行于横坐标的直线,与曲线交点的横坐标应分别为初凝时间和终凝时间;凝结时间结果应用h:min表示,精确至5min。 11.0.5应以三个试样的初凝时间和终凝时间的算术平均值作为此次试验初凝时间和终凝时间的试验结果。三个测值的最大值或最小值中有一个与中间值之差超过中间值的10%时,应以中间值作为试验结果;最大值和最小值与中间值之差均超过中间值的10%时,应重新试验。 12泌水试验 12.0.1本试验方法宜用于骨料最大公称粒径不大于40mm的混凝土拌合物泌水的测定。 12.0.2泌水试验的试验设备应符合下列规定: 1容量筒容积应为5L,并应配有盖子; 2量筒应为容量100mL、分度值1mL,并应带塞; 3振动台应符合现行行业标准《混凝土试验用振动台》JG/T 245的规定; 4捣棒应符合现行行业标准《混凝土坍落度仪》JG/T 248的规定; 5 电子天平的最大量程应为20kg,感量不应大于1g。 12.0.3泌水试验应按下列步骤进行: 1用湿布润湿容量筒内壁后应立即称量,并记录容量筒的质量。 2混凝土拌合物试样应按下列要求装入容量筒,并进行振实或插捣密实,振实或捣实的混凝土拌合物表面应低于容量筒筒口30 mm±3mm,并用抹刀抹平。 1)混凝土拌合物坍落度不大于90mm时,宜用振动台振实,应将混凝土拌合物一次性装入容量筒内,振动持续到表面出浆为止,并应避免过振; 2)混凝土拌合物坍落度大于90mm时,宜用人工插捣,应将混凝土拌合物分两层装入,每层的捅捣次数为25次;捣棒由边缘向中心均匀地插捣,插捣底层时捣棒应贯穿整个深度,插捣第二层时,捣棒应插透本层至下一层的表面;每一层捣完后应使用橡皮锤沿容量筒外壁敲击5次~10次,进行振实,直至混凝土拌合物表面插捣孔消失并不见大气泡为止; 3)自密实混凝土应一次性填满,且不应进行振动和插捣。 3应将筒口及外表面擦净,称量并记录容量筒与试样的总质量,盖好筒盖并开始计时。 4在吸取混凝土拌合物表面泌水的整个过程中,应使容量筒保持水平、不受振动;除了吸水操作外,应始终盖好盖子;室温应保持在20℃±2℃。 5计时开始后60min内,应每隔10min吸取1次试样表面泌水;60min后,每隔30min吸取1次试样表面泌水,直至不再泌水为止。每次吸水前2min,应将一片35mm±5mm厚的垫块垫入筒底一侧使其倾斜,吸水后应平稳地复原盖好。吸出的水应盛放于量筒中,并盖好塞子;记录每次的吸水量,并应计算累计吸水量,精确至1mL。 12.0.4混凝土拌合物的泌水量应按式(12.0.4)计算。泌水量应取三个试样测值的平均值。三个测值中的最大值或最小值,有一个与中间值之差超过中间值的15%时,应以中间值作为试验结果;最大值和最小值与中间值之差均超过中间值的15%时,应重新试验。 (12.0.4) 式中:Ba——单位面积混凝土拌合物的泌水量(mL/mm2),精确至0.01mL/mm2; V——累计的泌水量(mL); A——混凝土拌合物试样外露的表面面积(mm2)。 12.0.5混凝土拌合物的泌水率应按下列公式计算。泌水率应取三个试样测值的平均值。三个测值中的最大值或最小值,有一个与中间值之差超过中间值的15%时,应以中间值为试验结果;最大值和最小值与中间值之差均超过中间值的15%时,应重新试验。 (12.0.5-1) m=m2-m1 (12.0.5-2) 式中:B——泌水率(%),精确至1%; Vw——泌水总量(mL); m——混凝土拌合物试样质量(g); mT——试验拌制混凝土拌合物的总质量(g); W——试验拌制混凝土拌合物拌合用水量(mL); m2——容量筒及试样总质量(g); m1——容量筒质量(g)。 |
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GB/T 50080-2016, GB 50080-2016, GBT 50080-2016, GB/T50080-2016, GB/T 50080, GB/T50080, GB50080-2016, GB 50080, GB50080, GBT50080-2016, GBT 50080, GBT50080 |