Asbestos-Cement Pipe Failure Analysis

Challenge

Three pieces of an asbestos-cement pipe section were submitted to C3S, Inc. for evaluation after concerns regarding the pipe’s condition and potential failure. The investigation focused on identifying deterioration within the pipe wall and determining factors that may have contributed to cracking.~

Services Performed

C3S, Inc. evaluated the pipe section selected as representative of the most deteriorated condition. The investigation included:

• Condition assessment of the asbestos-cement pipe.
• Evaluation of carbonation within the pipe wall.
• Petrographic examination of the pipe material.
• Examination of cracks and deterioration zones.
• Microscopic evaluation of asbestos fibers and cementitious material.
• Assessment of potential factors contributing to pipe failure.

Testing Methods

• Phenolphthalein Testing — evaluation of carbonation depth and distribution.
• ASTM C856 — Petrographic Examination
• ASTM C1723-10 — SEM/EDX Examination
• Optical Microscopy — examination of pipe cross-sections, cracks, carbonated layers, and asbestos fibers.

Test

Petrographic Examination of Hardened Concrete

Examination by petrographic analysis showed three distinct carbonated areas and two uncarbonated areas. The extremities of the pipes are carbonated and about the mid-section of the pipe where a crack appears also show a band of carbonated layer.

Figure 3b shows a crack in an uncarbonated layer.

Figure 3d shows a partially carbonated area on the outer wall of pipe. (Mag. 400X)

Findings

Petrographic examination identified three distinct carbonated areas and two uncarbonated areas across the pipe wall.

Carbonation was observed near the inner and outer surfaces of the pipe, as well as in a band near the middle portion of the pipe wall where a crack was present. Microscopic examination also identified bundled and individual asbestos fibers within the pipe matrix.

A crack was observed within an uncarbonated layer, while the surrounding pipe wall exhibited varying degrees of carbonation.

Outcome

C3S, Inc. determined that carbonation within a band of the pipe wall closer to the inner surface may have contributed to the cracking observed near the middle section of the pipe wall.

The investigation provided the client with a detailed assessment of the pipe’s material condition and deterioration characteristics to support evaluation of the pipe’s remaining serviceability and potential failure mechanisms.

Featured Services:

• Pipe Failure Analysis
• Petrographic Examination
• Carbonation Evaluation
• SEM/EDX Analysis
• Asbestos-Cement Pipe Condition Assessment