Cement board with water-resistant additive
In the present disclosure, a cement board is disclosed. The cement board comprises a core having a first surface and a second surface opposite the first surface and a binder including a pozzolan material and a water-resistant additive, wherein the water-resistant additive is present in an amount of less than 5 wt. % based on the weight of the pozzolan material.
1. A cement board, comprising:
a core having a first surface and a second surface opposite the first surface and
a binder including a pozzolan material comprising fly ash, blast furnace slag, metakaolin, silica fume, microsilica, or a mixture thereof and
a water-resistant additive comprising a fatty acid including a backbone carbon chain having from 12 to 60 carbon atoms, wherein the water-resistant additive is present in an amount of less than 5 wt. % to 0.3 wt. % or more based on the weight of the pozzolan material.
2. The cement board of claim 1 , wherein the binder further comprises a cement.
3. The cement board of claim 2 , wherein the cement comprises Portland cement, magnesia cement, alumina cement, calcium sulphoaluminate cement, or a mixture thereof.
4. The cement board of claim 1 , wherein the binder further comprises gypsum.
5. The cement board of claim 1 , wherein the pozzolan material comprises blast furnace slag, metakaolin, silica fume, microsilica, or a mixture thereof.
6. The cement board of claim 1 , wherein the pozzolan material comprises fly ash.
7. The cement board of claim 1 , wherein the core further comprises a normal weight aggregate, a lightweight aggregate, or a mixture thereof.
8. The cement board of claim 7 , wherein the normal weight aggregate comprises sand, limestone, stone, shale, clay, granite, or a mixture thereof.
9. The cement board of claim 7 , wherein the lightweight aggregate comprises expanded shale, expanded clay, expanded vermiculite, expanded perlite, expanded pumice, expanded glass, expanded polystyrene, polyurethane, hollow spheres, or a mixture thereof.
10. The cement board of claim 7 , wherein the lightweight aggregate comprises expanded polystyrene beads.
11. The cement board of claim 10 , wherein the expanded polystyrene beads have a bimodal particle size distribution.
12. The cement board of claim 1 , wherein the core further comprises a retarder, an accelerator, or a mixture thereof.
13. The cement board of claim 1 , wherein the core further comprises a sulfonate, a cellulose polymer derivative, a polysaccharide, a galactomannan, or a mixture thereof.
14. The cement board of claim 1 , wherein the fatty acid comprises a fatty acid metal salt.
15. The cement board of claim 1 , wherein the fatty acid comprises from 12 to 24 carbon atoms.
16. The cement board of claim 1 , wherein the fatty acid comprises myristic acid, palmitic acid, arachidonic acid, montanic acid, octadecanoic acid, parinaric acid, or a mixture thereof.
17. The cement board of claim 1 , wherein the fatty acid comprises stearic acid.
18. The cement board of claim 14 , wherein the fatty acid metal salt comprises an alkaline earth metal.
19. The cement board of claim 1 , wherein the cement board indicates a water penetration having an area of 0.2 in 2 or less as determined in accordance with ANSI A118.10 and ASTM D4068, Annex A2.
20. The cement board of claim 1 , wherein the cement board exhibits a water absorption of 8 wt. % or less as determined in accordance with ASTM C473.
21. The cement board of claim 1 , wherein the cement board exhibits a water vapor permeance of 10 Perms or more as determined in accordance with ASTM E 96/E96M-16, Procedure B.
22. The cement board of claim 1 , wherein the cement board exhibits a fastener hold of from 50 lb f to 200 lb f as determined in accordance with ASTM C1396 and ASTM C473.
23. The cement board of claim 1 , wherein the cement board exhibits a modulus of rupture of from 500 psi to 2,000 psi as determined in accordance with ASTM C78.
24. The cement board of claim 1 , wherein the water-resistant additive is present in an amount of 3 wt. % or less to 0.3 wt. % or more based on the weight of the pozzolan material.