【法规名称】
【法规编号】 79807 什么是编号？
【正 文】
第11页 CAP 123B BUILDING (CONSTRUCTION) REGULATIONS
|
[接上页] 20 D and above 5 MPa 3 MPa Below 20 D 2 MPa 2 MPa(4) If the average strength determined from any group of 4 consecutive test results does not satisfy Column A of Table 8 then the batches of concrete represented by the first and last samples in the group and all intervening batches shall be deemed not to have attained the specified grade strength. (5) If an individual test result does not satisfy Column B of Table 8 then only the particular batch of concrete from which the sample was taken shall be deemed not to have attained the specified grade strength provided that the averages of all groups of 4 consecutive results in which the individual test result appears all satisfy Column A of Table 8. (6) If the requirements in subregulation (1) are not satisfied by any test result, investigations shall be made to establish whether the concrete represented by the test result is acceptable or not. (7) If the difference between the compressive strengths of any pair of cubes made from the same sample of concrete for specified grade strength 20 D and above exceeds 15% of the test result for that pair of cubes action shall be taken to ensure that the sampling and testing procedures as required under regulation 58 are being followed. (8) If the difference between the compressive strengths of any pair of cubes made from the same sample of concrete for specified grade strength 20 D and above exceeds 20% of the test result for that pair of cubes that test result shall be disregarded and investigations shall be made to establish whether the concrete represented by the test result is acceptable or not. (Enacted 1990) Cap 123B reg 60 Concrete for minor structural and non-structural works Prescribed mix concrete (1) Concrete may be a prescribed mix concrete as an alternative to designed mix concrete when it is used in minor structural or non-structural works. (2) Prescribed mix concrete shall be denoted by the specified grade strength in MPa with the suffix P. (3) Prescribed mix concrete shall be made using mix proportions, batching by weight, selected from Table 9 depending on its intended use. (4) Prescribed mix concrete shall comply with regulations 51, 52, 54, 61 and 62. (5) The cement used in prescribed mix concrete shall be ordinary Portland cement. TABLE 9 PRESCRIBED MIX CONCRETE Specified grade strength Material Weight of aggregate per bag of cement kg 45 kg bag of cement 50 kg bag of cement 10 P Fine aggregate 145 160 20 mm coarse aggregate 185 205 15 P Fine aggregate 120 130 20 mm coarse aggregate 165 180 20 P Fine aggregate 95 105 20 mm coarse aggregate 145 160 (Enacted 1990) Cap 123B reg 61 Formwork Construction (1) The formwork for concrete shall support safely the combined effects of all loads so that the final concrete structure is within the limits of acceptable dimensional tolerances. (2) The minimum period which must elapse before formwork may be removed shall not be less than that given in Table 10. TABLE 10 MINIMUM PERIOD BEFORE STRIKING FORMWORK Type of formwork Minimum period before formwork may be removed Vertical formwork to column, walls and large beams 12 hours Soffit formwork to slabs with props left in 4 days Soffit formwork to beams with props left in 7 days Props to slabs 10 days Props to beams 14 days (Enacted 1990) Cap 123B reg 62 Minimum cover of reinforcement (1) Subject to Part XV, the thickness of the concrete cover to reinforcement (exclusive of plaster rendering or other applied covering or decorative finish) shall not be less than the size of that reinforcement or the dimension as specified in Table 11, whichever is the greater and the cover to the ends of bars shall not be less than 25 mm. TABLE 11 MINIMUM THICKNESS OF CONCRETE COVER TO REINFORCEMENT Specified grade strength Reinforced concrete Prestressed concrete Slabs and walls in enclosed buildings Conditions of exposure Conditions of exposure Moderate Severe Moderate Severe 20 25 30 35 40 45 mm 30 30 30 25 25 25 mm -- 40 35 30 30 30 mm -- -- 30 25 20 20 mm -- -- 35 30 25 25 mm 20 20 20 15 15 15(2) In marine works or where the concrete is exposed to particularly corrosive conditions or where the concrete is made with lightweight aggregates the cover shall be suitably increased. (Enacted 1990) Cap 123B reg 63 Core testing Further testing (1) When concrete is considered from visual inspection to be suspect or when the specified grade strength has been deemed not to be attained under regulation 59 the compressive strength of the concrete in the structure may be determined by drilling a sufficient number of cores from the concrete at suitable locations. (2) The nominal minimum size of the core shall be 150 mm diameter for 40 mm aggregate and 100 mm diameter for 20 mm aggregate or less, and the length of the test sample cut from the core shall be at least 95% of the core diameter. (3) Cores drilled from concrete shall be prepared and tested by a recognized method to determine compressive strength. |
- 此法规有错误，我来纠正。请点击在此 提交错误内容或者您纠正的内容！