METHOD FOR PLACEMENT OF ROLLER COMPACTED CONCRETE (RCC) ON A SUB-BASE TO PRODUCE A CONCRETE PAVEMENT

Abstract

A method for placement of roller compacted concrete (RCC) on a sub-base to produce a concrete pavement, which has: (a) dosing a concrete or concrete ingredients and loading the concrete or concrete ingredients into a concrete transportation truck, (b) adding at least one pelletizing agent to the concrete and waiting from 3 to 15 minutes under constant mixing to produce a pelletized concrete and (c) discharging the pelletized concrete obtained in step (b) on the sub-base from the concrete transportation truck, rotating the drum of the concrete transportation truck.

Claims

1. A method for placement of roller compacted concrete (RCC) on a sub-base to produce a concrete pavement, wherein it comprises: (a) dosing a concrete or concrete ingredients and loading said concrete or concrete ingredients into a concrete transportation truck, (b) adding at least one pelletizing agent to the concrete and waiting from 3 to 15 minutes under constant mixing to produce a pelletized concrete and (c) discharging the pelletized concrete obtained in step (b) on the sub-base from the concrete transportation truck, rotating the drum of the concrete transportation truck.

2. The method according to claim 1, wherein the VB value of said pelletized concrete is classified as V0 to V2.

3. The method according to claim 1, wherein the discharge of the pelletized concrete in step (c) is directly done on the sub-base and uniformly distributed manually or mechanically and pressed using a roller.

4. The method according to claim 1, wherein the discharge of the pelletized concrete in step (c) is done into an asphalt paver.

5. The method according to claim 1, wherein the concrete once placed on the sub-base is compacted using a roller.

6. The method according to claim 1, wherein the concrete of step (a) comprises a self-curing agent and/or an air-entraining agent.

7. The method according to claim 6, wherein a solid active content of said self-curing agent is at a concentration between 0.1-5% (w/w).

8. The method according to claim 6, wherein said self-curing agent is selected from the group consisting of polyvalent alcohol, phytosterols, hyaluronic acid, polyxyethylene (POE), sodium pyrrolidone carboxylate (PCA-Na), cetyl alcohol, stearyl alcohol and poly-acrylic acid.

9. The method according to claim 8, wherein said polyvalent alcohol is selected from the group consisting of polyethylene glycol (PEG), propylene glycol (PG), dipropylene glycol (DPG), butylene glycol, neopently glycol, xylitol, sorbitol and glycerine.

10. The method according to claim 7, wherein the solid active content of said air-entraining agent is at a concentration between 0.1-5% (w/w).

11. The method according to claim 6, wherein said air-entraining agent is selected from the group consisting of salts of wood resins, salts of proteinaceous material, fatty acids, resinous acids, fatty salts, resinous salts, alkylbenzene sulfonate salts, salts of alkyl sulfonates, polyoxyethylene alkyl sulfonate salts, polyoxyethylene alkylaryl ethers, salts of sulfonated lignin and derivatives of hydrocarbon sulfonates.

12. The method according to claim 1, wherein in step (b) the solid active content of the pelletizing agent is at a concentration between 0.3-3 kg/m3 of concrete.

13. The method according to claim 1, wherein said pelletizing agent is selected from the group consisting of cellulose, chitosan, polyacrylics, polyamines, polyvinylalcohols, polysaccharides, collagen, acrylamide, lactic acid, methacrylic acid, methacrylate, hydroxyethyl, ethylene glycol, ethylene oxide, acrylic acid, inorganic flocculants and inorganic coagulants.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0089] FIG. 1. Slump values of a concrete over time.

[0090] FIG. 2. VEBE time determined according to European Standard EN 12350-3:2009 for concretes with different amounts of pelletizing agent.

[0091] FIG. 3. VEBE time determined according to European Standard EN 12350-3:2009 for concretes with different amounts of pelletizing agent.

[0092] FIG. 4. Detection of Pellets in concrete after adding a pelletizing agent.

EXAMPLES OF THE INVENTION

Example 1

[0093] S3 slump class concrete was produced and the slump was monitored over time. The results are shown on FIG. 1.

Example 2

[0094] S3 slump class concrete was produced, and different amounts of the pelletizing agent were then added. The VEBE time was determined according to European Standard EN 12350-3:2009 for all concretes and the results are shown in FIGS. 2 and 3.

Mix Design

[0095]

TABLE-US-00002 Cement CEM OPC Optimo 40 R 230 kg/m.sup.3 Water addition 146 kg/m.sup.3 Superplasticizer (PCE) 2.3 kg/m.sup.3 Air-Entrainer (Vinsol Resin) 2% (w/w) Sand 912 kg/m.sup.3 inch Aggregate 1.184 kg/m.sup.3

Example 3

[0096] S3 slump class concrete with self-curing agent was produced, and the pelletizing agent was then added. The appearance of visual pellets in the concrete was detected over time and the results are shown in FIG. 4.

Mix Design

[0097]

TABLE-US-00003 Raw Material kg/m.sup.3 CEM I 300 w/c 0.54 0/4 round 889 4/8 crushed 719 8/11 crushed 339 Superplasticizer (PCE) 3.67 Self-curing agent (PEG) 3 Polysaccharide 1.333

[0098] The pellets were discharged from the drum of the concrete truck and poured directly into the sub-base. A roller compacted said pellets to finish the job. Due to the use of a self-curing agent, no need for posterior curing was needed.

Example 4

[0099] 7 m.sup.3 of concrete were produced at a ready-mix plant and introduced in a concrete truck. This concrete had the following composition: [0100] 1.260 kg of cement CEM OPC Optimo 40 R [0101] 490 kg fly ash [0102] 18.2 kg superplasticizer (polycarboxylate ether-based (PCE)) [0103] 6.398 kg sand [0104] 8.316 kg aggregates (1.9 cm size)

[0105] 0.917 m.sup.3 of water were then added to the concrete truck and rotation of the drum started in order to mix the concrete. This concrete had a theoretical density of 2.465. The truck transports the concrete to the jobsite with permanent rotation of the drum. The jobsite was situated 40 min away from the ready-mix plant, therefore the pelletizing agent was only added at the jobsite. At the jobsite, 9.1 kg of pelletizing agent were added to the drum and mixed for 4 minutes with the concrete mix. During these 4 minutes, a clear change of the concrete consistency was observedthe fluid concrete was substituted by a granular material inside the truck. By reversing the movement of the drum, this granular material was discharged from the truck and placed into the paver that placed the granular materials as road bed, following the traditional procedure for normal RCC. After, the concrete was compacted using a traditional roller.

Example 5

[0106] 4 m.sup.3 of concrete were prepared at a central-mix plant with the following mix design:

TABLE-US-00004 Ordinary Portland Coarse Cement Fly ash Superplasticizer Sand Aggregate [Kg/m.sup.3] [kg/m.sup.3] w/c (w/w) (% vol) (% vol) 190 60 0.60 0.60% 47% 53%

[0107] The blend is pre-mixed in the central plant and discharged into the concrete truck which continues the mixing. Because the jobsite is only 5 minutes away from the central mix, pelletizing agent is also added at the plant, before the truck leaves to the jobsite. Once arrived at the jobsite, the drum is already filled with granular material, which is then discharged directly into the sub-base. Once placed, the roller compacts the concrete, finishing the process.