protective coating of access chambers...powerpoint presentation author martins silins created date...

Protective Coating of Access Chambers

•Manholes

•Maintenance Holes

•Utility Holes

•Access Chambers

•Utility Vaults

Manhole as % of Total Sewer Area

Pipeline Diameter

150mm 225mm 300mm

Distance between manholes

50m 30% 22% 17%

60m 26% 19% 15%

70m 23% 17% 13%

Manhole Diameter:1050mm

Manhole Depth:2.5m

Manhole Infiltration

Potential Reasons for Manhole Deterioration

• Leaking joints

• Infiltration through loose mortar and pre-cast joints

• Leaks around pipe ends

• Cracks in the structure

• Corrosion

Potential Reasons for Deterioration

Manholes are becoming plastic

Manhole Rehabilitation Contract

•Investigation / Assessment•Recommendations•Do the Work

Classes of Manhole Rehabilitation

• Sacrificial Protective Coating– Cementitious Products

• Permanent Protective Coating– Polyurea / Epoxy / Polyurethanes

• Re-Build Coating– Epoxy Mortar

• Reconstruction

Determining the Appropriate Solution

Depth of Loose Material Removed Solution

0 – 20mmStructural integrity of the access chamber is still intact.Protective Coating

20mm – up to steel reinforcing

Structural integrity is compromised and structural repair is necessary.Rebuild Coating:

Beyond steel reinforcing Complete Rebuild or replacement.

Restore before its too late …

0200400600800

100012001400160018002000

Cost ($/m2)

Nothing ProtectiveCoating

RebuildCoating

CompleteStructuralRebuild

Determining the Appropriate Solution

Opportunity for person access to determine the extent of

the deterioration

Condition Assessment

Manhole Assessment Report

Condition Assessment Report


S604

Condition Assessment Report – Core Samples

S604


S601


S807 Wall


S807 Base

Preparing the Surface

Remove the deteriorated concrete

Surface Preparation

g

1

32 4

FIGURE 1

200mm

Concrete surface must be hard

Surface Preparation

Concrete surface must be clean

Surface Preparation

Concrete surface must be acid neutralised

Application Conditions

Substrate surface moisture measurement


Ambient Humidity and Temperature


Surface Temperature

Protective Coating – Polyurea

• Spray applied

• Ultra fast curing resin

• Tough and hard wearing

• Water tight

• Chemically resistant

• Flexible – can handle vibrations

Polyurea Application

Stage 1:Apply Epoxy Primer

Apply to test piece to be left in manhole


Primer Cure Test

Durometer measures surface hardness in 5 places


Spray polyurea coating at 3mm thickness


Has it cured?

Measure hardness


Has it adhered?


Inspect for pinholes, bubbles

Polyurea Properties

• Chemical Resistance: High (pH 2 to 12): ISO175

• Abrasion Resistance: ASTM D460 1,000 cycles– Polyurea: <6mg– PVC: 25mg– Epoxy: 50mg

• Elongation: 425%: ASTM D412

Polyurea Properties

• Hardness: (Shore D) 60: ASTM D2240

• Impact Resistance: (high): ASTM G14

Polyurea

Rebuild Coating : Epoxy Mortar

• General purpose epoxy based rebuild

• 20mm standard thickness

• Applied by hand / spray

• Tough and hard wearing

• Water tight

• Chemically resistant

Rebuild Coating : Epoxy Mortar

Example: Original Condition

Example: After Jetting

Example: Completed

Epoxy Mortar Properties

• Compressive Strength: 60MPa

• Chemical Resistance: pH 2 to pH 12 ISO 175

• Hardness : (similar to concrete)

• Adhesion to concrete: 3.5MPa (concrete fails)

• Abrasion Resistance: many times higher than concrete

Epoxy Mortar Properties

• Yield Strength– Epoxy Mortar: 22MPa– PVC: 45MPa– Concrete: 3 – 5MPa

• Short Term Modulus– Epoxy Mortar: 4,200MPa– PVC: 3,200MPa

Summary

• An important component of complete sewer rehabilitation

• Separate Protection and Repair Solutions are available. Early intervention leads to $ savings

• Proper condition evaluation needed

• Proper surface preparation needed for success

• These systems offer permanent protection

protective coating of access chambers...powerpoint presentation author martins silins created date...

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