ASTM D4552/D4552M-20 (2025) PDF

Full title and description

St ASTM D4552/D4552M-20 (2025) — Standard Practice for Classifying Hot‑Mix Recycling Agents. This practice establishes a standardized classification system for recycling (rejuvenating) agents used in hot recycling of asphalt concrete, based primarily on kinematic viscosity measured at 60 °C (140 °F). The designation shown (D4552/D4552M-20(2025)) indicates the 2020 edition with formal reapproval/reconfirmation in 2025.

Abstract

This standard provides a simple, product‑level classification for hot‑mix recycling agents (RAs) so that suppliers, laboratories, agencies and contractors can describe and compare products intended for use in hot recycling of asphalt concrete. Classification is by kinematic viscosity at 60 °C and the practice also references additional physical/property thresholds (flash point, saturates content, residue aging behavior, specific gravity) used to screen materials for safe handling and plant use. The standard does not itself evaluate final pavement performance of binder blends or mixtures containing the recycling agents.

General information

• Status: Current — 2020 edition, reapproved/reconfirmed in 2025 (often shown as D4552/D4552M‑20(2025)).
• Publication date: 2020 (edition year); reapproval/reconfirmation date: May 1, 2025 (reaffirmation recorded in 2025).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: Road and paving materials / road construction materials — ICS codes commonly associated: 93.080.10 and 93.080.20 (road construction / road construction materials).
• Edition / version: D4552/D4552M‑20 (R2025) — 2020 edition with 2025 reapproval.
• Number of pages: 4 pages (concise practice document).

Scope

This practice covers a standardized method for classifying recycling agents intended for hot recycling of asphalt concrete by their kinematic viscosity measured at 60 °C (140 °F). It applies to liquid recycling agents (including petroleum‑based and non‑petroleum organic products) but does not apply to emulsified recycling agents. The practice does not prescribe or predict pavement performance of mixes or binders after recycling; it is a classification/screening tool to support safe handling, selection and plant use.

Key topics and requirements

• Classification by kinematic viscosity at 60 °C: defined RA grades (example common RA classes: RA‑0, RA‑1, RA‑5, RA‑25, RA‑75, RA‑250, RA‑500) with non‑overlapping viscosity ranges for each grade. Typical viscosity ranges (cSt at 60 °C) used in the practice are: RA‑0 (≈10–49), RA‑1 (≈50–175), RA‑5 (≈176–900), RA‑25 (≈901–4,500), RA‑75 (≈4,501–12,500), RA‑250 (≈12,501–37,500), RA‑500 (≈37,501–60,000).
• Supplementary screening properties referenced: minimum flash point (safety handling), maximum saturates content (wt%), viscosity ratio on residue after short‑term oven aging, allowable mass change after aging, and typical specific gravity ranges — these are included to help assess safety, handling and basic durability/suitability for plant use. Typical thresholds cited in guidance include flash point ≥ 219 °C, saturates ≤ ~30 wt%, viscosity ratio limits (RTFO/TFOT residue) generally ≤ 3 and limited mass change after oven aging (varies by grade).
• Test conditions and units: kinematic viscosity in mm²/s (cSt) measured at 60 °C; the practice provides SI and inch‑pound unit presentation but treats each system separately (do not mix unit systems within acceptance criteria).
• Limitation: does not address emulsions; does not replace binder or mixture performance tests (users are directed to relevant binder specifications and performance grading standards when assessing final mix behavior).

Typical use and users

Primary users are pavement engineers, DOT specification writers, asphalt plant operators, materials laboratories, recycling agent manufacturers and consultants. The practice is used to (1) classify and label recycling agents for procurement and specification, (2) provide screening data for safe plant handling and storage, and (3) help agencies select an appropriate viscosity class of RA to match recycled‑binder targets before proceeding to mixture or binder performance testing.

Related standards

Referenced and related ASTM standards commonly used with D4552/D4552M include binder and aging test methods and specifications such as ASTM D2872 (TFOT), ASTM D6373 (performance graded asphalt binder), ASTM D8239, ASTM D946/D946M and ASTM D3381/D3381M (as noted in practice guidance), plus local agency mixture and binder specifications for recycled materials.

Keywords

recycling agent, rejuvenator, hot‑mix recycling, RA classification, viscosity at 60 °C, asphalt, RAP, RAS, hot recycling, bitumen, ASTM D4552.

FAQ

Q: What is this standard?

A: ASTM D4552/D4552M‑20(2025) is a short ASTM practice that classifies liquid recycling agents intended for hot recycling of asphalt concrete by kinematic viscosity (measured at 60 °C) and provides screening guidance for basic physical/safety properties.

Q: What does it cover?

A: It covers classification by viscosity for non‑emulsified recycling agents, and refers to supplementary property thresholds (flash point, saturates content, residue aging behavior, specific gravity) to help screen materials for safe handling and plant suitability. It does not evaluate or guarantee pavement or binder performance of mixes containing the agents.

Q: Who typically uses it?

A: State DOTs and highway agencies, materials laboratories, contractors and asphalt plant operators, recycling agent suppliers, and pavement researchers use it to label, specify and screen RAs before further binder/mix performance testing.

Q: Is it current or superseded?

A: The 2020 edition is the current edition and it was formally reapproved/reconfirmed in 2025 (hence the designation D4552/D4552M‑20(2025) for the reapproval). Users should check with ASTM or their national standards body for the latest status and any amendments.

Q: Is it part of a series?

A: It is a stand‑alone practice within ASTM Committee D04 (Road and Paving Materials) and is often used alongside related ASTM binder and aging specifications (for example D6373, D2872, D946/D946M and D3381/D3381M) when assessing recycled binder blends and recycled hot‑mixes.

Q: What are the key keywords?

A: Recycling agent, rejuvenator, RA grading, viscosity at 60 °C, hot‑mix recycling, RAP, RAS, asphalt, D4552.