Room temperature cured green concrete derived from natural pozzolan and nanosilica

Patent metadata

Field	Value
Publication number	US-11414353-B2
Application number	US-201916391685-A
Country	US
Kind code	B2
Filing date	Apr 23, 2019
Priority date	Apr 23, 2019
Publication date	Aug 16, 2022
Grant date	Aug 16, 2022

Abstract

A green concrete and mortar compositions free of Portland cement are disclosed. The compositions comprise Natural pozzolan, nanosilica particles, and alkaline activator. The green concrete produced from the composition of the invention is cured at ambient temperature and has higher compressive strength than that of concrete made with Portland cement.

First claim

The invention claimed is:

1. A Portland cement-free green concrete composition, comprising:
silicon dioxide nanoparticles;
alkaline activators; and
natural pozzolan,
wherein the silicon dioxide nanoparticles have an average surface area in the range of 20 m 2 /g to 150 m 2 /g.

2. The green concrete composition of claim 1 , wherein the silicon dioxide nanoparticles are present in an amount in the range of 0.5 wt. % to 10 wt. % of the total weight of the natural pozzolan.

3. The green concrete composition of claim 1 , wherein the amount of the silicon dioxide nanoparticles is in the range 4 wt. % to 8 wt. % of the total weight of the pozzolan.

4. The green concrete composition of claim 1 , wherein the silicon dioxide nanoparticles have an average size in the range of 10 nm to 500 nm.

5. The green concrete composition of claim 1 , wherein the alkaline activators include an alkali metal silicate and an alkali metal hydroxide.

6. The green concrete composition of claim 5 , wherein the weight ratio of the alkali silicate to the alkali hydroxide is in a range of 2.4:1 to 2.7:1.

7. The green concrete composition of claim 5 , wherein the alkali metal silicate is sodium silicate.

8. The green concrete composition of claim 5 , wherein the alkali metal hydroxide is sodium hydroxide.

9. The green concrete composition of claim 5 , which has a weight percentage of the alkali hydroxide ranging from 1.5-5% relative to a total weight of the alkali activated concrete composition.

10. The green concrete composition of claim 5 , which has a weight percentage of the alkali silicate ranging from 5-10% relative to a total weight of the green concrete composition.

11. The green concrete composition of claim 1 , which has a weight percentage of the natural pozzolan ranging from 8-20% relative to a total weight of green concrete composition.

12. The green concrete composition of claim 1 , further comprising fine and coarse aggregates.

13. The green concrete composition of claim 12 , wherein a weight ratio of the coarse aggregate to the fine aggregate is in a range of 3:1 to 1:1.

14. A wet concrete slurry, comprising:
the green concrete composition of claim 1 ; and
water,
wherein a weight ratio of the water to the alkali activated concrete composition is in a range of 1:5 to 1:25.

15. A method of producing a green concrete comprising:
casting the wet concrete slurry of claim 14 in a mold to form a casted wet concrete; and
curing the casted wet concrete for 1-90 days at ambient temperature thereby forming the alkali activated concrete.

16. The composition of claim 1 , further comprising fine aggregates.

17. The composition of claim 16 , wherein the amount of the silicon dioxide nanoparticles is in the range 4 wt. % to 8 wt. % of the total weight of the pozzolan.

18. A Portland cement-free green concrete composition, comprising:
silicon dioxide nanoparticles;
alkaline activators; and
natural pozzolan,
wherein the alkaline activators include an alkali metal silicate and an alkali metal hydroxide, and
wherein the weight ratio of the alkali silicate to the alkali hydroxide is in a range of 2.4:1 to 2.7:1.

19. A Portland cement-free green concrete composition, comprising:
silicon dioxide nanoparticles;
alkaline activators; and
natural pozzolan,
which has a weight percentage of the natural pozzolan ranging from 8-20% relative to a total weight of green concrete composition.

20. The composition of claim 19 , wherein the alkaline activators include an alkali metal silicate and an alkali metal hydroxide, and
wherein the alkali silicate is present in a range of from 5 to 10 wt. % relative to a total weight of the concrete composition, and/or
wherein the alkali hydroxide is present in a range of from 1.5 to 5 wt. % relative to the total weight of the concrete composition.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Ibrahim Mohammed
• Maslehuddin Mohammed
• Rahman Muhammed Kalimur
• Dafallah Hatim Mohamad
• Johari Megat Azmi Megat

Classifications

• C04B28/006 Primary

  containing mineral polymers, e.g. geopolymers of the Davidovits type · CPC title

• C04B28/26 Primary

  Silicates of the alkali metals · CPC title

• C04B14/14

  Minerals of vulcanic origin {(granite C04B14/048)} · CPC title

• C04B2111/1037

  Cement free compositions, e.g. hydraulically hardening mixtures based on waste materials, not containing cement as such · CPC title

• C04B40/065

  Two or more component mortars · CPC title