Alkali-activated concrete containing palm oil fuel ash

Patent metadata

Field	Value
Publication number	US-2021039997-A1
Application number	US-201916533014-A
Country	US
Kind code	A1
Filing date	Aug 6, 2019
Priority date	Aug 6, 2019
Publication date	Feb 11, 2021
Grant date	—

Abstract

A concrete composition that includes (i) a treated palm oil fuel ash, wherein the treated palm oil fuel ash is the only binder present, (ii) a fine aggregate, (iii) a coarse aggregate, and (iv) an alkali activator containing an aqueous solution of sodium hydroxide and sodium silicate. A cured concrete made from the concrete composition is also disclosed with advantageous compressive strength properties.

First claim

1 . A concrete composition, comprising:
a treated palm oil fuel ash, wherein the treated palm oil fuel ash is the only binder present; a fine aggregate; a coarse aggregate; and an alkali activator comprising an aqueous solution of sodium hydroxide and sodium silicate.

2 . The concrete composition of claim 1 , wherein the treated palm oil fuel ash is present in an amount of 20 to 30 wt. %, based on a total weight of the concrete composition.

3 . The concrete composition of claim 1 , wherein the treated palm oil fuel ash is obtained sequentially from drying raw palm oil fuel ash at 80 to 120° C., sieving to a particle size of less than 300 μm, a first mechanical ball milling, calcining at 500 to 600° C., and a second mechanical ball milling.

4 . The concrete composition of claim 1 , wherein the treated palm oil fuel ash has a median particle size (d 50 ) of 0.5 to 2.0 μm.

5 . The concrete composition of claim 1 , wherein the treated palm oil fuel ash comprises, as constituent oxides, 60 to 72 wt. % SiO 2 , 4 to 8 wt. % Al 2 O 3 , 3 to 7 wt. % Fe 2 O 3 , 3 to 8 wt. % CaO, 1 to 5 wt. % MgO, 3 to 7 wt. % K 2 O, 0.2 to 0.5 wt. % SO 3 , 0.1 to 0.25 wt. % Na 2 O, and 1 to 5 wt. % of P 2 O 3 , each based on a total weight of the treated palm oil fuel ash.

6 . The concrete composition of claim 1 , wherein the treated palm oil fuel ash comprises, as constituent oxides, 66 to 68 wt. % SiO 2 , 6 to 7 wt. % Al 2 O 3 , 5 to 6.5 wt. % Fe 2 O 3 , 5 to 6 wt. % CaO, 2.5 to 3.5 wt. % MgO, 4.5 to 6 wt. % K 2 O, 0.3 to 0.35 wt. % SO 3 , 0.18 to 0.2 wt. % Na 2 O, and 3 to 4 wt. % of P 2 O 3 , each based on a total weight of the treated palm oil fuel ash.

7 . The concrete composition of claim 1 , wherein the treated palm oil fuel ash has a loss on ignition (LOI) of less 3 wt. %, based on a total weight of the treated palm oil fuel ash, and a specific surface area of 1.4 to 1.6 m 2 /g.

8 . The concrete composition of claim 1 , wherein a weight ratio of a combined weight of the coarse aggregate and the fine aggregate to the treated palm oil fuel ash is 1:1 to 2:1.

9 . The concrete composition of claim 1 , wherein the fine aggregate has a fineness modulus of 1.8 to 2.1 and a saturated surface dry (SSD) specific gravity of 2.5 to 2.7.

10 . The concrete composition of claim 1 , wherein the coarse aggregate has a saturated surface dry (SSD) specific gravity of 2.4 to 2.6.

11 . The concrete composition of claim 1 , wherein the coarse aggregate has a bimodal particle size distribution with a first mode particle size of 4 to 6 mm and second mode particle size of 2 to 3 mm, and a wherein a weight ratio of coarse aggregate having the first mode particle size to coarse aggregate having the second mode particle size is 1:1 to 3:1.

12 . The concrete composition of claim 1 , wherein a weight ratio of the coarse aggregate to the fine aggregate is 1:1 to 2:1.

13 . The concrete composition of claim 1 , wherein the alkali activator is formed from an aqueous solution of sodium hydroxide having a sodium hydroxide concentration of 10 to 14 mol/L.

14 . The concrete composition of claim 1 , wherein a weight ratio of the alkali activator to the treated palm oil fuel ash is 0.3:1 to 0.7:1

15 . The concrete composition of claim 1 , wherein a weight ratio of sodium silicate to sodium hydroxide is 1:1 to 3:1

16 . The concrete composition of claim 1 , which has weight ratio of water to the treated palm oil fuel ash of 0.06 to 0.98.

17 . The concrete composition of claim 1 , which consists of the treated palm oil fuel ash, the coarse aggregate, the fine aggregate, sodium hydroxide, sodium silicate, and water.

18 . A cured concrete comprising the concrete composition of claim 1 in cured form.

19 . The cured concrete of claim 18 , which has a 28-day compressive strength of 33 to 49 MPa.

20 . The cured concrete of claim 18 , which has a unit weight of 2200 to 2300 kg/m 3 .

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Salami Babatunde Abiodun
• Johari Megat Azmi Megat
• Maslehuddin Mohammed
• Ahmad Zainal Arifin

Classifications

• Y02P40/18

  Carbon capture and storage [CCS] · CPC title

• Y02W30/91

  Use of waste materials as fillers for mortars or concrete · CPC title

• C04B28/021

  Ash cements, e.g. fly ash cements (fly ash as filler C04B18/08); Cements based on incineration residues, e.g. alkali-activated slags from waste incineration (alkali-activated combustion residues as such C04B7/243; mixtures of the lime-pozzuolane type C04B28/18); Kiln dust cements · CPC title

• C04B18/101 Primary

  Burned rice husks or other burned vegetable material · CPC title

• C04B28/26 Primary

  Silicates of the alkali metals · CPC title