Fast-setting flowable fill compositions, and methods of utilizing and producing the same
Fast-setting flowable fill compositions for filling ground trenches are described. The compositions set quickly but retain a low strength psi at 28 days. The compositions also reduce bleed water on the surface of the fast-setting flowable fill and therefor enable quicker application of surface repair material, e.g., pavement patches, to the trench. The compositions consist of aggregate, Portland cement, accelerant, water and sometimes air. The compositions may have a compressive strength of between 5 psi and 60 psi after 2 hours, a compressive strength of between 10 psi and 100 psi after 4 hours, a compressive strength of between 75 psi and 500 psi after 28 days, a penetration resistance of between 1.5 tsf and 75 tsf after 2 hours, a penetration resistance of between 4.5 tsf and 200 tsf after 4 hours, and a shrinkage of less than 2% as measured by ASTM C490. Also disclosed are methods of filling a trench with fast-setting flowable fill.
1. A method of filling a trench comprising:
(a) mixing a composition, the composition including the following:
between 60% and 88.75% aggregate by weight of the composition;
between 3% and 25% Portland cement by weight of the composition;
between 0.25% and 8% accelerant by weight of the composition; and
between 8% and 35% water by weight of the composition;
the composition having a compressive strength of between 40 psi and 300 psi after 1 day, a compressive strength of between 60 psi and 375 psi after 7 days and a compressive strength of between 80 psi and 700 psi after 28 days; and
(b) filling the trench with the composition.
2. The method of claim 1 , wherein the aggregate is between 70% and 80% by weight.
3. The method of claim 1 , wherein the aggregate is fine aggregate.
4. The method of claim 1 , wherein the aggregate is a combination of coarse aggregate and fine aggregate.
5. The method of claim 1 , wherein the aggregate is a combination of fine aggregate and micro aggregate.
6. The method of claim 5 , wherein the micro aggregate is dust that is collected in the baghouses of asphalt plants, cement plants, or other industrial facilities that generate and collect dust.
7. The method of claim 1 , wherein the aggregate is a combination of coarse aggregate and sand.
8. The method of claim 1 , wherein the aggregate is recycled trench spoils.
9. The method of claim 1 , wherein the Portland cement is between 4% and 13% by weight of the composition.
10. The method of claim 1 , wherein the accelerant is between 1% and 4.5% by weight of the composition.
11. The method of claim 10 , wherein the accelerant is sodium carbonate, sodium bicarbonate, calcium chloride, non-chloride accelerator, or some combination thereof.
12. The method of claim 11 , wherein the accelerant is sodium bicarbonate.
13. The method of claim 1 , wherein the water is between 12% and 17% by weight.
14. The method of claim 1 , wherein the aggregate is sand between 70% and 80% by weight of the composition;
the Portland cement is between 4% and 13% by weight of the composition;
the accelerant is sodium bicarbonate between 0.5% and 5% by weight of the composition; and
the water is between 10% and 17% by weight of the composition.
15. The method of claim 1 further comprising micro aggregate between 5% and 40% by weight of the composition.
16. The method of claim 1 further comprising a water reducer greater than 2.0 fluid ounces per cubic yard of the composition.
17. The method of claim 1 further comprising a polymer.
18. The method of claim 17 , wherein the polymer is less than 0.1% by weight of dry solids in the composition.
19. The method of claim 17 , wherein the polymer is hydroxypropyl methylcellulose.