Reinforced drain quality appraisal

steel drainage pipe is based on the core principle of the synergy between concrete compression resistance and steel bar crack resistance. By optimizing the steel skeleton reinforcement ratio, concrete strength grade and centrifugal forming process, it achieves the synergy of resistance to external pressure load, impermeability and durability. It is widely used in municipal drainage, highway culverts, farmland irrigation and industrial sewage discharge. In municipal engineering, it is used in the main rainwater and sewage pipe network; in the transportation field, it meets the anti-settlement requirements of culvert structures; in agricultural scenarios, it ensures the freeze-thaw resistance of irrigation channels. Compared with ordinary concrete pipes, reinforced drainage pipes have strong impact resistance, excellent interface sealing, and long service life. They are key components for safe drainage in underground projects.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide quality appraisal services for reinforced drainage pipes. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for the quality appraisal of reinforced drainage pipes.

With the expansion of urban underground pipe network construction, related quality dispute cases have increased significantly. The judicial dispute focuses on:

1, performance index dispute: the external pressure resistance test failed to meet the standard, and the leakage test failed;

2, material defects: the chloride ion content of concrete exceeded the standard, and the thickness of the protective layer of steel bars Deficiencies;

3, process problems: out-of-control centrifugal molding speed leads to delamination, and insufficient vulcanization of the rubber ring;

4, contract performance disputes: shrinkage of pipe length, interface type does not match technical agreement.

1. Appearance inspection: Visually inspect the appearance of the drain pipe to see if there are cracks, damage, pores and other defects on the surface.

2. Dimensional measurement: Use vernier calipers or steel rulers to measure the length, inner diameter, outer diameter and other dimensions of the drainage pipe, and compare with the design drawings.

3. Compressive strength test: Place the drain pipe in a pressure testing machine, apply a certain pressure, and record the rupture pressure of the drain pipe.

4. Water absorption test: Soak the drain pipe sample in water for a certain period of time and measure its water absorption rate.

5. Freeze-thaw resistance test: Place the drain pipe samples alternately in the freeze-thaw cycler to observe their freeze-thaw resistance.

A municipal company of the applicant signed a "DN1200 reinforced drainage pipe purchase contract" with a pipe factory of the respondent, and it was agreed that the external pressure resistance should be ≥180kN/m. After construction, the pipe body collapsed, causing the road surface to collapse. The manufacturer argued that the backfill soil was not compacted enough.

Identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of "Reinforced Drainage Pipes", contract technical agreements, on-site investigation case materials and other data, and made the following quality analysis opinions:

The concrete strength of the reinforced drainage pipe involved in the case is only 25MPa (design C35), and the spacing deviation of the steel skeleton reaches ±30mm (standard ±10mm); the cracking load of the pipe body in the external pressure test was 120kN/m (agreed ≥180kN/m), and the protective layer of the steel bars was only 8mm in part (agreed 25±5mm).

The appraisal conclusion concluded that insufficient material strength and workmanship defects were the main causes of crushing.

Reinforced drainage pipe quality appraisal report should include:

1, appraisal purpose and reference standards;

2, specification of the pipe involved, production batch number, construction record;

3, testing method Methods and equipment list;

4, correlation analysis of test data and failure;