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A portland cement and low-heat technology, applied in the cement field, can solve problems such as concrete cracking, and achieve the effects of increasing cement toughness, flexural strength, and volume stability
Inactive Publication Date: 2013-06-12
CHINA THREE GORGES CORPORATION
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Problems solved by technology
[0004] In order to solve the cracking problem of concrete in the prior art, the present invention provides a low-heat crack-resistant Portland cement for hydraulic concrete
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Embodiment 1
[0018] A low-heat crack-resistant Portland cement, the mineral composition of the cement clinker is: dicalcium silicate: 45.5%, tricalcium silicate: 30.4%, tricalcium aluminate: 3.2%, tetracalcium aluminoferrite: 20.4%, free calcium oxide: 0.5%; the content of magnesium oxide in the cement is 4.2%, the content of alkali is 0.52%, and the content of sulfur trioxide is 3.2%, and the above percentages are percentages by weight.
[0019] The various technical indicators of the low-heat crack-resistant Portland cement are: loss on ignition: 2wt%, specific surface area: 320m 2 / kg, initial setting time: 90min, final setting time: 10h, stability: qualified, no requirement for 3-day compressive strength, 7-day compressive strength: 15.0MPa, 28-day compressive strength: 47.0MPa, 3 There is no requirement for the flexural strength of one day, the flexural strength of 7 days: 4.0MPa, the flexural strength of 28 days: 8.0MPa, the heat of hydration of 3 days: 200KJ / kg, the compressive stre...
Embodiment 2
[0022] A low-heat crack-resistant Portland cement, the mineral composition of the cement clinker is: dicalcium silicate: 70%, tricalcium silicate: 10%, tricalcium aluminate: 1%, tetracalcium aluminoferrite: 30%, free calcium oxide: 0.1%; the magnesium oxide content in the cement is 3.5%, the alkali content: 0.1%, the sulfur trioxide content: 1%, and the above percentages are percentages by weight.
[0023] The technical indicators of the low-heat crack-resistant Portland cement are: loss on ignition: 3wt%, specific surface area ≤ 300m 2 / kg, initial setting time: 60min, final setting time: 12h, stability: qualified, no requirement for 3-day compressive strength, 7-day compressive strength: 13.0MPa, 28-day compressive strength: 52.5MPa, 3 There is no requirement for the flexural strength of one day, the flexural strength of 7 days: 5MPa, the flexural strength of 28 days: 7.0MPa, the heat of hydration of 3 days: 220KJ / kg, the compressive strength of 7 days: 250KJ / kg.
[0024] W...
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Abstract
The invention discloses low-heat anti-cracking Portland cement. The cement clinker of the cement consists of the following minerals in percentage by weight: 40 to 70 percent of dicalcium silicate, 10 to 35 percent of tricalcium silicate, 1 to 4 percent of tricalcium aluminate, 15 to 30 percent of tetra calcium aluminoferrite, and 0.1 to 0.8 percent of free calcium oxide, wherein the content of magnesium oxide in the cement is between 3.5 and 5.0 percent, the content of alkali is not more than 0.55 percent, and the content of sulfur trioxide is not more than 3.5 percent. The cement has the main technical indexes that the ignition loss is less than or equal to 3wt%, the specific area is less than or equal to 340m<2>/kg, the stability is qualified, 3-day tensile strength is not required, the 7-day tensile strength is more than or equal to 13MPa, the 28-day tensile strength is between 42.5MPa and 52.5MPa, the 3-day breaking strength is not required, the 7-day breaking strength is more than or equal to 3.5MPa, the 28-day breaking strength is more than or equal to 7.0MPa, the 3-day hydration heat is less than or equal to 220KJ/kg, and the 7-day tensile strength is less than or equal to 250KJ/kg. The cement can be used for remarkably improving the cracking resistance of hydraulic concrete.
Description
technical field [0001] The invention relates to a cement, in particular to a low-heat crack-resistant Portland cement used for hydraulic concrete. Background technique [0002] In recent years, the speed of dam construction in my country has been accelerating, but the problem of concrete cracking has not been well resolved. As far as materials are concerned, cement is one of the most critical factors affecting concrete cracking. [0003] Hydraulic concrete (except concrete for flood discharge and energy dissipation buildings) has the characteristics of large volume, long design age, and generally low strength. It has high requirements for concrete crack resistance and durability. Therefore, cement is required to have low and slow heat of hydration. 1. It has a certain function of compensating for shrinkage. In special cases, it should also have the effect of preventing alkali aggregate reaction and sulfate erosion. Contents of the invention [0004] In order to solve the ...
Claims
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