Use of a naphthalenesulfonic acid polycondensate as a plasticizer in a construction composition and construction composition
A naphthalenesulfonic acid polycondensate is used as a plasticizer in a construction composition comprising sand and at least one cementitious binder. The naphthalenesulfonic acid polycondensate is obtainable by a condensation reaction of i) a naphthalenesulfonic acid, ii) an alkoxylated hydroxyaryl compound having a polyoxyalkylene chain with 3 to 130 oxyalkylene units, and iii) formaldehyde, in a weight ratio of i):ii) of 95:5 to 60:40, preferably 95:5 to 75:25, more preferably 95:5 to 85:15, wherein the sand has a methylene blue value according to DIN EN 933-9 of at least 10 g/kg. The naphthalenesulfonic acid polycondensate is largely clay-insensitive and its dispersibility is independent of the quality of the sand.
1 . A method of using a naphthalenesulfonic acid polycondensate for plasticizing a construction composition, the method comprising adding the naphthalenesulfonic acid polycondensate to the construction composition comprising sand and at least one cementitious binder, the naphthalenesulfonic acid polycondensate comprising a condensation reaction product of
i) a naphthalenesulfonic acid,
ii) an alkoxylated hydroxyaryl compound having a polyoxyalkylene chain with 3 to 130 oxyalkylene units, and
iii) formaldehyde,
in a weight ratio of i):ii) of 95:5 to 60:40,
wherein the sand has a methylene blue value according to DIN EN 933-9 of at least 10 g/kg.
2 . The method according to claim 1 , wherein the sand has a methylene blue value according to DIN EN 933-9 of 10 to 50 g/kg.
3 . The method according to claim 1 , wherein the polyoxyalkylene units comprise at least 60 mol-% of oxyethylene units.
4 . The method according to claim 1 , wherein the hydroxyaryl compound is selected from phenols and naphthols.
5 . The method according to claim 1 , wherein the alkoxylated hydroxyaryl compound ii) is an ethoxylated phenol or an ethoxylated naphthol.
6 . The method according to claim 1 , wherein the cementitious binder comprises a cement selected from Portland cement, calcium aluminate cement and sulfoaluminate cement.
7 . The method according to claim 6 , wherein the cementitious binder additionally comprises a latent hydraulic binder.
8 . The method according to claim 7 , wherein the latent hydraulic binder is blast furnace slag.
9 . The method according to claim 1 , wherein the construction composition, in freshly mixed form, has a ratio of water to cementitious binder in the range of 0.3 to 0.6.
10 . The method according to claim 1 , wherein the construction composition additionally comprises at least one retarder and/or accelerator.
11 . The method according to claim 1 , wherein the construction composition additionally comprises at least one dispersant other than the naphthalenesulfonic acid polycondensate.
12 . The method according to claim 1 , wherein the construction composition comprises, relative to the total amount of the construction composition,
the cementitious binder in an amount of 7 to 15 vol.-%,
sand in an amount of 25 to 30 vol.-%, and
coarse aggregates in an amount of 40 to 50 vol.-%.
13 . The method according to claim 12 , wherein the construction composition additionally comprises a supplementary cementitious material in an amount, relative to the weight of the cementitious binder, of 5 to 80 wt.-%.
14 . The method of claim 1 , wherein the weight ratio of i):ii) is 95:5 to 75:25.
15 . The method of claim 1 , wherein the weight ratio of i):ii) is 95:5 to 85:15.
16 . The method according to claim 1 , wherein the sand has a methylene blue value according to DIN EN 933-9 of 15 to 25 g/kg.
17 . The method according to claim 1 , wherein the sand has a methylene blue value according to DIN EN 933-9 of 20 to 30 g/kg.
18 . The method according to claim 1 , wherein the polyoxyalkylene units comprise at least 85 mol-% of oxyethylene units.
19 . The method according to claim 1 , wherein the polyoxyalkylene units comprise at least 95 mol-% of oxyethylene units.
20 . The method according to claim 1 , wherein the construction composition, in freshly mixed form, has a ratio of water to cementitious binder in the range of 0.35 to 0.4.
21 . A construction composition comprising
a) a naphthalenesulfonic acid polycondensate comprising a condensation reaction product of
a-i) a naphthalenesulfonic acid,
a-ii) an alkoxylated hydroxyaryl compound having a polyoxyalkylene chain with 3 to 130 oxyalkylene units, and
a-iii) formaldehyde,
in a weight ratio of i):ii) of 95:5 to 60:40,
b) at least one cementitious binder,
c) a sand having a methylene blue value according to DIN EN 933-9 of at least 10 g/kg, and
d) water.
22 . The construction composition of claim 21 , additionally comprising coarse aggregates.