Process for the manufacture of a bitumen-aggregate mix suitable for road pavement
View Patent ↗The present invention relates to an aqueous quick-setting bitumen-aggregate mix suitable for cold pavement of roads, parking places, sidewalks and the like. The bitumen-aggregate mix is manufactured by mixing a mineral aggregate, water, a de-emulsifier, containing hydraulic cement, and a cationic oil-in-water bitumen emulsion, containing, as an emulsifier, a salt of a tertiary diamine and a phosphoric acid. The diamine has the formula (I), where one or two of the groups R 1 , R 2 , R 4 and R 5 designate a hydrocarbon group of 6–22, preferably 8–20 carbon atoms, and the remaining R 1 , R 2 , R 4 and R 5 groups are an alkyl group with 1–4 carbon atoms, and/or a group —(A) 2 H, where A is an alkyleneoxy group with 2–3 carbon atoms, and s is a number from 1–4, R 3 is an alkylene group with 2–4 carbon atoms and n is a number from 0–2.
1. A method for manufacturing an aqueous bitumen-aggregate mix by mixing an oil-in-water bitumen emulsion containing an emulsifier, a mineral aggregate, additional water and a de-emulsifier at a temperature from 0 to 40° C., wherein the bitumen emulsion has a pH-value between 1–5 and the emulsifier contains a salt between a polyvalent phosphoric acid and a diamine of the formula
where one or two of the groups R 1 , R 2 , R 4 and R 5 designate a hydrocarbon group of 6–22 carbon atoms, and the remaining R 1 , R 2 , R 4 and R 5 groups are an alkyl group with 1–4 carbon atoms, and/or a group —(A) s H, where A is an alkyleneoxy group with 2–3 carbon atoms, and s is a number from 1–4, and R 3 is an alkylene group with 2–4 carbon atoms and the de-emulsifier contains a hydraulic cement.
2. The method of claim 1 , wherein the diamine of formula I contains at least one methyl group and at least one group of the formula (A) s H. where A is ethyleneoxy and s is 1.
3. The method of claim 2 , wherein the ratio of the average number of methyl groups to the average number of ethyleneoxy groups in the diamines of formula I is from 1:6 to 3:1.
4. The method of claim 1 , wherein the diamine of formula I contains a compound, where one or two of the groups R 1 , R 2 , R 4 and R 5 designate a hydrocarbon group of 6–22 carbon atoms and the remaining groups R 1 , R 2 , R 4 and R 5 are all methyl, or a compound, where the remaining groups R 1 , R 2 , R 4 and R 5 are all groups of the formula (A) s H, where A and s have the meaning as defined in claim 1 , or a mixture of these compounds.
5. The method of claim 4 , wherein the diamine of formula I contains a mixture of the two types of compounds as defined in claim 4 in a weight ratio from 1:10 to 10:1.
6. The method of the claim 1 , wherein the weight ratio between the diamine salt of the emulsifier and the cement is from 0.15–1.5.
7. The method of claim 1 wherein the phosphoric acid is orthophosphoric acid.
8. The method of claim 1 wherein the hydraulic cement is a Portland cement.
9. The method of claim 1 wherein the bitumen has an acid content between 0.05 and 1 mg KOH/g of the bitumen.
10. The method of claim 1 wherein one or two of the groups R 1 , R 2 , R 4 and R 5 designate a hydrocarbon group of 8–20 carbon atoms.
11. A diamine salt that comprises the product of a polyvalent phosphoric acid and a diamino of the formula
where one or two of the groups R 1 , R 2 , R 4 and R 5 designate a hydrocarbon group of 6–22 carbon atoms, and the remaining R 1 , R 2 , R 4 and R 5 groups are an alkyl group with 1–4 carbon atoms, and/or a group —(A) s H, where A is an alkyleneoxy group with 2–3 carbon atoms, and s is a number from 1–4, and R 3 is an alkylene group with 2–4 carbon atoms.
12. An acidic oil-in-water bitumen emulsion, characterized in that it has a pH-value between 1 and 5 and contains 0.4–20% by weight of the salt of claim 11 .
13. An aqueous bitumen-aggregate mix comprising
100 parts by weight of an aggregate,
6–20 parts by weight of bitumen,
0.1–3 parts by weight of the salt defined in claim 11 , and
0.1–2 parts by weight of hydraulic cement.