PQC: Pavement Qaulity Concrete Layer ।। Technical Specification Road Work

In this video we have explained in detail about Pqc i.e. Payment Quality Concrete, how we should work and what are the requirements?
In this video we have discussed about side and what are the requirements. We have discussed about practical knowledge and technical specification, what we should put in this and I am a side engineer. That's why I made this video. The intention of making this video is to share my knowledge.
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What is Pavement Quality Concrete? – PQC Construction Method

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PQC stands for Pavement Quality Concrete made with larger size aggregates following IRC specifications and laid over a Dry Lean Concrete(DLC), concrete subbase course. PQC construction is explicitly used for highway concrete pavements and runway pavements to take heavy loads. 

PQC Construction Method:

Plant and Machinery:

Excavator, Paver, Motor Grader, End dumpers, Vibro rollers(tyre mounted), Vibro rollers(smooth wheeled double drums), Concrete Batching Plant, Needle and screed vibrator etc. are required for PQC construction. 



PQC Construction Materials:

The following list of materials is essential for PQC construction.

20mm size aggregate

10m size aggregate

Crushed Stone dust and sand

OPC 43 grade

Admixture

Water

Dowel bar of 32mm dia from an approved source

Tie bar of 12mm dia from an approved source

Poly Sulphide sealant of approved brand

Epoxy of approved brand

Anchorage grouting compound of approved brand

Curing compound of approved brand

Separation membrane of specified thickness

PQC Construction Materials – Important Notes:

Cement:

Up to 20% of fly ash can be blended for PQC construction as a partial replacement of ordinary portland cement of grade 53 only.

GGBFS(Ground Granulated Blast Furnace Slag) conforming to IS:12089 shall not be used in any other grade of cement except 53 grade.

As per MoRTH, the minimum OPC content for PQC construction shall be 310 kg/cum in case of blending at the site, and Mix design will be done as per IRC:44.

In the case of the Portland Pozzolana Cement, fly ash content should be 25% or less for pavement concrete.

The cement used having sulphate resistant property and shall conform to IS:12330.

Chemical Admixtures:

Admixtures used for PQC construction work shall conform to IS:9103 and IS:6925.

The admixture’s solitary function is to improve the workability of the concrete or extension of setting time without affecting concrete properties concerning strength, volume change, durability, and no harmful effect on steel bars.

Fibres:

Steel(IRC SP:46) or polymeric synthetic fibres can be used to reduce the shrinkage cracking and post-cracking subjected to Designer approval.

The properties of fibres shall be as per MoRTH Section 600, clause 602.2.3.1.

Aggregate:

Aggregates used for PQC construction work shall conform to IS:383 and with a Los Angeles Abrasion value, not more than 35%.

Permissible deleterious materials content should be as per MoRTH table 600-2.

Chloride ion and the Sulphuric anhydride (SO3) content should not exceed 0.06% and 0.25% by weight, respectively.

For pavement concrete, The maximum size of coarse aggregate shall not exceed 31.5mm.

We shall not accept the water absorption of more than 2% in pavement concrete mix.

The soundness of aggregate shall be tested as per IS:2386 (Part-5), and the loss shall not be more than 12% if sodium sulphate solution is used or 18% if magnesium sulphate solution is used.

The combined Flakiness Elongation index of aggregate should be 35% or less for PQC construction.

Fine aggregates:

The fine aggregates for PQC construction work may be clean natural sand or crushed stone dust or a combination of the above conforming to IS:383. It should be free from soft particles, clay, shale, loam, cemented particles, mica and organic and other foreign matter. It is essential to investigate the mica content of fine aggregate before mix design and make suitable allowances for the possible reduction in concrete strength.

Water : 

As per IS:456, it should be clean and free from harmful oil, salt, acid, vegetable matter or other substances. 

Mild steel bars for dowels and tie bars :

Dowel Bar having a yield stress of Fe-240 shall be of plain mild steel conforming to IS:432.

Tiebar having yield stress of Fe-500 shall be of TMT steel and shall conform to IS:1786.



Pre moulded joint filler : 

As per IS:1838, or BS:2630, a firm compressible Joint filler board for expansion joints is used only at adjoining structures like bridges with a thickness of 20-25mm± 1.5mm.