Services

Full Depth Reclamation

What is ANT Full Depth Reclamation (FDR)

Full-depth reclamation (FDR) is a sustainable pavement rehabilitation technique. It involves pulverizing the existing asphalt layers along with a portion of the underlying base material. This mixture is then stabilized with additives like cement, bitumen, or chemical stabilizers to create a new, strong base layer.

FDR offers several advantages, including cost-effectiveness, environmental friendliness (reduced waste), and improved pavement performance. However, careful consideration must be given to the existing pavement condition and the suitability of the underlying layers. Maintaining adequate embankment and subgrade heights is crucial for the success of the FDR process.

ANT full-depth reclamation (ANT FDR) relies on the reduction-oxidation reactions (redox reactions), in the presence of ANT Stabilizer, accompanied by consolidation of pulverized existing pavement material for its strength. There are many advantages of using ANT Stabilizer :-

No Curing Required: Unlike traditional cement-based stabilization, ANT Stabilizer doesn’t require a curing period after compaction. This significantly reduces construction time and allows for rapid traffic loading.
Environmentally Friendly: ANT Stabilizer is safe for human handling and the environment, minimizing potential negative impacts.
Improved Pavement Performance: It enhances the strength, durability, and resistance to deformation of the pavement, leading to a longer service life.
Utilization of Marginal Materials: Allows for the use of locally available materials like RAP (Reclaimed Asphalt Pavement), stone dust, and mining waste, reducing reliance on virgin aggregates and promoting sustainability.
Cold weather: Suitable for construction in various weather conditions, including during short periods of dry weather between rains, increasing construction efficiency.
Versatility: Compatible with a wide range of mineral materials, providing flexibility in material selection and adaptation to local conditions.
Rapid Construction: Allows for quick construction and immediate traffic loading after compaction, minimizing traffic disruptions and project timelines.

ANT Soil Stabilizer

Full-depth-reclamation (FDR) using “ANT” technology is based on use of the “ANT” soil stabilizer which is a complex organic product. It enters into redox reactions with molecular oxygen on surfaces of aggregate and soil particles. New crystalline bonds established between the particles due to redox reactions lead to formation of monolithic stone-like structure that mimics sedimentary rocks created by Mother Nature through the natural processes. The stabilizer is a liquid product. It is dissolved into the water to be used for mixing pulverized existing pavement material and cement. The methodology of FDR can be broadly divided into three parts namely Sampling Methodology, Mix Design Methodology and Construction Methodology.

Sampling Methodology

Full depth samples of existing asphalt pavement and underlying granular layers are collected from the site to determine the physical properties of existing pavement material.
Sampling interval - minimum one every Km. at varying offsets from centerline.
Auger sampling or open pits sampling or a combination of both is used.
During sampling, the sampling team makes visual observations of existing roadway.
In case of major distress, the frequency is increased.
Also, in case of major rutting distress, clients are advised to get Dynamic Cone Penetration (DCP) tests done in such areas to assess the in-situ strength of sub-grade.
In case of varying gradation along road length, it is ensured that samples are taken from all types of gradations.

Mix Design Methodology

Mix design methodology consists of determining gradation of the sample, optimum moisture content of mix, maximum dry density of mix, unconfined compressive strength (UCS) of mix, durability of mix and preparation of mix design report.
Materials from samples delivered to the laboratory are blended in a manner that will replicate the reclaiming operations during construction. Gradation of materials should meet criteria given in the table below. However, if the gradation obtained is different, then additional material of desired sizes shall be mixed and mix design can be done to meet the desired gradation.
Various tests conducted for mix design are as follows: –

S No.	Tests	Test Method
1	Gradation of sample	Specification For Road And Bridge Works, 5th Revision, Ministry Of Road Transport & Highways and IRC :SP : 89 (Part-II)-2018
1	Optimum Moisture Content	IS:2720(part-2)
3	Maximum Dry Density	IS:2720 (part 7 & 8)
4	Unconfined Compressive Strength (UCS)	IRC :SP : 89 (Part-II)-2018
5	Durability	IRC :SP : 89 (Part-II)-2018

Based on the results obtained in above listed test, the job mix report is prepared and it contains following information:

Gradation of existing pavement material
Liquid limit, Plastic Limit, and Plasticity Index of combined material (if applicable)
Maximum dry density and Optimum Moisture Content (OMC) of the mix
Unconfined compressive strength at each trial cement content
Wet density of UCS test specimens before and immediately after moist curing period
Recommended cement content as a percentage of dry materials
Recommended stabilizer content as per mix design
Source information for Portland cement

Construction Methodology

Construction methodology involves calculation of quantities, deployment of machinery and execution at site. Methodologies for these activities are as given below: –

Methodology of Calculations of Quantities

Quantity calculations are given below: –

Quantity of aggregate and soil mix (Qa) to be stabilized is calculated
Quantity of water (Qw) needed to bring the aggregate, cement, soil and water mix to Optimum Moisture Content (OMC) is calculated. Proper care is taken to account for existing moisture contents of the aggregate and soil
Qw = Qa x OMC%
Quantity of ‘ANT’ Stabilizer (Qs) is calculated using the formula
Qs = Qa x P%
(P% factor is as per the job mix)
Quantity of cement (Qc) is calculated using the formula
Qc = Qa x C%
(C% factor is as per the job mix)

Equipment/ Machinery Required

Water Tanker (6 Kl/12 Kl) capacity
Trucks to transfer material
Grader to spread the mix and leveling at site
Cement Spreading Machine
Recycler Machine
Vibratory/ Smooth Wheel Roller (>15 ton)
Tandem
Pneumatic Tyre Roller (PTR)

Methodology of Execution

The soil stabilization is executed carefully so that the stabilized layer meets strength parameters as per IRC:37-2018 and. IRC SP:89: 2010 & Part II, 2018. The steps for execution of work at site are as follows: –

1. Mixing of “ANT” stabilizer in tanker as per the required quantities of water and stabilizer. Aqueous solution of ANT is allowed to mature for a minimum period of 10 minutes.

2. Spreading of cement homogeneously with help of cement Spreader.

3. Deploying the tanker containing “ANT” stabilizer aqueous solution. The tanker moves in-front of the recycler and is connected to it through a pipe to supply the said aqueous solution.

4. Deploying recycler to: –

Pulverize existing pavement material up to design depth
Inject dose of aqueous solution of “ANT” stabilizer required as per job mix into the mixing chamber where it gets mixed with pulverized existing pavement material and pre-spread cement.
Spreading the mix over road surface true to required grade through the screed

5. Compaction by making required passes of tandem/ smooth wheeled roller and then required passes using PTR to achieve a minimum 98% of compaction.

Compaction is started after 60 minutes of in-situ mixing and laying by the recycler. “ANT” stabilizer takes approx. 60 minutes to react with cement/soil particles. However, the material can be compacted up to 8 hours after mixing and laying by recycler.
Passes overlap 1/3rd of preceding pass, speed of the roller is maximum 5km/hr. The places not accessible to roller shall be compacted with mechanical tampers.

6. Rectification of all the dispersions and segregations (if any) during initial rolling itself.

7. Testing after final rolling is completed to ascertain degree of compaction with respect to MDD of design mix. All the field density reading / results are recorded in specified format.

8. Checking surface levels and recording in the specified format. Levels are maintained as per Table no. 900-1 (MoRTH Specification).

9. Allowing slow traffic movement on the compacted layer any-time after 30 minutes of compaction and regular traffic movement on the compacted layer any-time after 4 hours.

Notes

1. Curing is not necessary; however if curing is done, it does not affect the strength.

2. In case the mixing of pulverized existing pavement material, aqueous solution of “ANT” Stabilizer and cement is done in plant, the mixed material can be laid at the site using grader/paver as per the required profile and thickness.

3. The surface of the stabilized layer shall be cleaned and any loose material should be removed from it before the next layer is started.

4. Bitumen prime coat should be applied within one week after final compaction.

5. The bituminous layer over this stabilizer layer may be laid as per the standard procedure.

Methodology of Testing Quality of Work

In order to ensure each stabilized layer meets the prescribed requirement of specifications quality checks are conducted as per table 14 of IRC: SP: 89-2010.

S No.	Quality Tests	Test Method	Minimum Desired Frequency
1	Quality of Cement	As per relevant Indian standards	Once initially for approval of the source of supply and later for each consignment of the material.
1	Moisture Content	IS:2720(part-2)	One test per 250 sqm
3	Density of Compacted layer	IS:2720 part 28 or 29	One test per 500 sqm
4	CBR or UCS on a set of 3 specimen	IS:2720 (part-16) IS:4332 (part-5)	One test per 3000 cum of mix
5	Thickness of layer	-	Regularly
6	Cement content	-	Regularly through procedural checks
7	ANT Stabilizer Dosage	-	Regularly through procedural checks
8	Durability of stabilized material	IRC SP: 89 ( part -II) -2018,	Apart from above routine tests, durability of stabilized material is also tested

Acceptance Criteria

1. The degree of compaction shall not be less than 98% of laboratory MDD of blended material.

2. The layer thickness tolerance shall be +/- 10 mm

Storage and Handling of Cement

Cement bags are stored properly so that cement used for stabilization is always fresh. Cement is stored in sound watertight buildings and cement bags are stacked as tightly as possible. The cement which is delivered first is used first.

Safety Precautions

1. All precaution should be taken while movement of machinery & equipment on the work site.

2. All staff and workers should use PPEs as per work requirement.

3. Good traffic control system should be done while execution after the work.

4. proper lighting arrangement should be done during work in night hours.