Use of calcium sulfate in an inorganic mortar system based on aluminous cement to increase load values
An inorganic mortar system for a chemical fastening of an anchor in a mineral surface includes calcium sulfate, a component A, and a component B for initiating a curing process. Component A includes water, aluminous cement, at least one plasticizer, and at least one blocking agent selected from phosphoric acid, metaphosphoric acid, phosphorous acid, and a phosphonic acid. Component B includes an initiator, at least one retarder, at least one mineral filler, and water. Component A is also a curable composition.
1. An inorganic mortar system for a chemical fastening of an anchor in a mineral surface, the inorganic mortar system comprising:
calcium sulfate,
a curable aluminous cement component A, and
an initiator component B for initiating a curing process,
wherein component A comprises water, a calcium aluminate cement, at least one plasticizer, and at least one blocking agent selected from the group consisting of phosphoric acid, metaphosphoric acid, phosphorous acid, and a phosphonic acid,
component B comprises an initiator comprising LiOH, at least one retarder, at least one mineral filler, and water,
component A and component B are separate,
a ratio of calcium aluminate cement comprising calcium sulfate to lithium hydroxide ((CAC+CaSO 4 )/LiOH) in the product obtained by mixing components A and B is in the range of from 1.3:1 to 12.5:1,
the calcium sulfate in the product obtained by mixing components A and B is present in the range of from about 0.95 wt.-% to 18.0 wt.-% and
a mortar prepared from said inorganic mortar system has a chemical shrinkage of from −0.61 to −1.61.
2. The inorganic mortar system according to claim 1 , wherein
component A comprising an aqueous-phase calcium aluminate cement.
3. The inorganic mortar system according to claim 1 , wherein
the calcium sulfate is in the form of calcium sulfate anhydrite, calcium sulfate hemihydrate or calcium sulfate dihydrate.
4. The inorganic mortar system according to claim 1 , wherein
the calcium sulfate is present in component A.
5. The inorganic mortar system according to claim 4 , wherein
the calcium sulfate is present in component A in a ratio of calcium sulfate to calcium aluminate cement in a range of from 5/95 to 30/70.
6. The inorganic mortar system according to claim 1 , wherein
the initiator comprises a mixture of at least two of an alkali metal salt, an alkaline earth metal salt, and a combination thereof,
the at least one retarder is selected from the group consisting of citric acid, tartaric acid, lactic acid, salicylic acid, gluconic acid, and a mixture thereof, and
the at least one mineral filler is selected from the group consisting of a limestone filler, sand, corundum, dolomite, alkaline-resistant glass, crushed stone, gravel, pebble, and a mixture thereof.
7. The inorganic mortar system according to claim 1 , wherein
the initiator comprises a mixture of at least two lithium metal salts.
8. The inorganic mortar system according to claim 1 , wherein
the ratio of water to calcium aluminate cement comprising calcium sulfate (W/(CAC+CaSO 4 )) in the product obtained by mixing components A and B is lower than 1.0.
9. The inorganic mortar system according to claim 1 , wherein
the anchor is an anchor rod, a threaded anchor rod, a bolt, or a steel reinforcement bar.
10. The inorganic mortar system according to claim 1 , wherein
the mineral surface is a structure comprising brickwork, concrete, pervious concrete, or natural stone.
11. The inorganic mortar system according to claim 1 , wherein
the mineral surface is a wet borehole.
12. The inorganic mortar system according to claim 1 , wherein
the mineral surface is a diamond drilled borehole.
13. A method of chemical fastening of an anchor in a mineral surface, the method comprising:
setting the anchor in a borehole present in the mineral surface in the presence of the inorganic mortar system according to claim 1 ; and
curing the inorganic mortar system, thereby increasing a load value of the borehole filled with a cured inorganic mortar system compared to a load value of a borehole without the cured inorganic mortar system.
14. A method of chemical fastening of an anchor in a mineral surface, the method comprising:
setting the anchor in a borehole present in the mineral surface in the presence of the inorganic mortar system according to claim 1 ; and
curing the inorganic mortar system, thereby increasing a load value of the borehole filled with a cured inorganic mortar system, thereby decreasing shrinkage of a cured inorganic mortar system in the borehole compared to a load value of a borehole without the cured inorganic mortar system.
15. The method according to claim 13 , wherein
the anchor is a metal element; and
the mineral surface is at least one member selected from the group consisting of brickwork, concrete, pervious concrete, and natural stone.