AASHTO M 86M/M 86-2023 - Nonreinforced Concrete Sewer, Storm Drain, and Culvert Pipe

Standard No.: AASHTO M 86M/M 86-2023
Release Date: 2023
Published By: American Association of State Highway and Transportation Officials US / AASHTO
Latest: AASHTO M 86M/M 86-2023

Introduction

Standard Overview and Technical Background

Standard M86M/M86-23, published by the American Association of State Highway and Transportation Officials (AASHTO), is a key technical specification for the manufacture and procurement of unreinforced concrete pipe. This standard, which underwent technical and editorial revisions in 2023, supersedes the previous version and reflects the latest developments in concrete pipe technology. This standard applies to the construction of unreinforced concrete pipes and culverts for conveying sewage, industrial wastewater, and stormwater, providing a critical technical basis for infrastructure construction.

Material Composition and Mixture Requirements

The standard sets clear requirements for the composition of concrete materials: cementitious materials must conform to the M85 Portland cement specification, or slag Portland cement, limestone Portland cement, and fly ash Portland cement conforming to the M240M/M240 specification. Notably, the standard allows for a variety of cementitious material combinations, including eight mix ratios, such as single cement, cement and fly ash combinations, and cement and slag combinations.

Material type

Standard basis

Technical requirements

Application limitations

Portland cement

M85

Meet Type IV requirements

Can be used alone

Fly ash

M295

Grade F or Grade C

Need to be mixed with cement

Slag cement

ASTM C989/C989M: Grade 100 or 120, with limited dosage. Aggregates: M6 and M80, gradation requirements exempted. Clean and free of impurities. The water-cement ratio must not exceed 0.53, and the cementitious material content must be at least 280 kg/m³. These stringent requirements ensure the durability and impermeability of concrete. The standard also allows the use of synthetic and non-synthetic fibers as non-structural materials, but they must comply with the requirements of ASTM C1116/C1116M. Pipe Classification and Strength Requirements: The standard classifies unreinforced concrete pipes into three strength classes: Class 1, Class 2, and Class 3, each with different minimum wall thickness and load-bearing capacity requirements. This classification method is based on the different pipe use environments and load requirements, providing flexible options for engineering design.

Nominal diameter (mm)	Class 1 minimum wall thickness (mm)	Class 1 load capacity (kN/m)	Class 2 minimum wall thickness (mm)	Class 2 load capacity (kN/m)	Class 3 minimum wall thickness (mm)	Class 3 Carrying capacity (kN/m)
100	41	22.0	48	29.0	48	35.0
15 0	48	22.0	48	29.0	57	3 5.0
200	48	22.0	57	29 .0	73	35.0
250	57	23.5	64	29.0	82	35.0
300	64	26.5	89	33.0	111	38.0

The load-bearing capacity test is conducted using the three-side support method, requiring that at least 75% of the tested pipes meet the specified strength requirements. This grading system ensures the safety and economy of pipelines in different application scenarios.

Manufacturing process and curing requirements

The standard sets out detailed requirements for the manufacturing process of concrete pipes. The mixture must be uniform, and the aggregates need to be properly graded and proportioned. The curing process can adopt various methods such as steam curing, water curing or membrane curing to ensure that the concrete reaches the specified strength properties.

Steam curing requires that the pipes be placed freely in the curing room and maintain an appropriate temperature and humidity environment; water curing requires the use of water-saturated materials to cover or a spray system to keep the pipes moist; membrane curing requires the use of a sealing membrane that complies with ASTM C309 and construction within the atmospheric temperature range of ±6°C. These curing requirements ensure that the concrete hydration reaction proceeds fully and the final strength is achieved.

Physical performance testing and acceptance standards

The standard specifies four key performance tests: external load crushing test, water absorption test, permeability test and hydrostatic pressure test. Each test has clear acceptance criteria and sampling requirements.

Test Items

Test Methods

Acceptance Criteria

Sampling Ratio

Crushing Strength

T280

Meet the requirements of Table 1

0.5% (at least 2 pieces)

Water Absorption

Boiling Method

≤9%

Same as Strength Test Permeability: T280; 80% of pipes free of damp spots; 2% (minimum 2 pipes); Hydrostatic Pressure: T280; No leakage for 10 minutes at 70kPa; 0.5% (minimum 2 pipes); Test sampling varies based on order size: small orders (less than 100 pipes) require a standard test report, while large orders require proportional sampling. If more than 20% of the samples fail, the manufacturer may conduct a screening and rejection. However, if the second sampling still fails, the entire batch will be rejected.

Dimensional Tolerances and Quality Control

The standard has strict regulations on pipe dimensional tolerances: the inner diameter tolerance ranges from ±5mm to ±10mm depending on the pipe diameter; the wall thickness tolerance is 2-5mm or 5% of the wall thickness value; the length tolerance is -13mm; the difference in length between the two end faces does not exceed 6mm or 2% of the nominal diameter; and the straightness requirement does not exceed 10mm per meter.

These tolerance requirements ensure smooth pipe installation and system sealing. At the same time, the standard allows for local wall thickness variations, as long as physical testing requirements are met, which provides a certain degree of flexibility in the manufacturing process.

Implementation Recommendations and Engineering Applications

In actual engineering applications, it is recommended to focus on the following aspects: First, correctly select the pipe grade according to the actual use environment and load conditions. Class 1 is suitable for low load conditions and Class 3 is suitable for heavy load conditions. Second, strictly monitor the concrete mix ratio and water-cement ratio to ensure durability requirements. Third, strengthen the curing process control to ensure strength development. Fourth, conduct sampling tests in accordance with standard requirements to ensure product quality.

Pay special attention to the tips in Note 1 of the standard: This specification is only a manufacturing and procurement specification and does not include requirements for bedding, backfill, or the relationship between on-site load conditions and pipe strength grades. Successful product performance depends on the correct selection of pipe grades, bedding and backfill types, and installation in accordance with construction specifications. The owner must correlate site requirements with the specified pipe grade and provide or require inspection at the construction site.

Technological Evolution and Standard Comparison

The 2023 edition of the standard features major technological evolutions compared to previous versions, including updated referenced standards, improved cementitious material combinations, detailed curing temperature control requirements, and strengthened testing and acceptance procedures. It is consistent with ASTM C14M-20 and C14-20, ensuring the standard's universality and applicability.

The standard also places special emphasis on sustainability, allowing the use of industrial by-products such as fly ash and slag, which reduces production costs and minimizes environmental impact. This technological approach aligns with the green development trend of modern infrastructure construction.

Quality Control and Inspection Requirements

Inspection of the final product includes visual inspection, dimensional measurement, and performance testing. Pipeline surfaces must be free of cracks that affect strength, durability, or performance. Local repairs are permitted, but the repaired pipe must meet all code requirements. Each pipe must be clearly marked with the pipe grade, manufacturing date, manufacturer name, and factory logo.

Rejection criteria include: cracks that penetrate the pipe wall or joints, non-vertical end faces, mixing and molding defects, cracks that affect performance, etc. These strict quality control requirements ensure the reliability and safety of the pipeline during service.

AASHTO M 86M/M 86-2023 history

2023 AASHTO M 86M/M 86-2023 Nonreinforced Concrete Sewer, Storm Drain, and Culvert Pipe

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