On April 23, Palace Museum expert Zhou Qian confirmed in his new book that the pig blood lime mortar used in Forbidden City restoration is a protein-lime reaction-enhanced traditional building material with excellent moisture resistance and crack resistance, and has been verified through modern materials science. This technique is being incorporated into the White Paper on Export Technology for Chinese Ancient Building Restoration Materials, providing localized data support for EU CE certification and adaptation to U.S. ASTM standards. Related niche sectors such as ancient building restoration material manufacturing, export trade, and international heritage conservation technical services deserve attention—this development marks the shift of traditional Chinese construction craftsmanship from experience-based inheritance to scientific validation and standards alignment, with its impact extending beyond cultural relic protection into compliant building material exports, cross-border technical services, and standards coordination.

Event Overview

On April 23, Palace Museum expert Zhou Qian explicitly stated in his new book that the pig blood lime mortar used in Forbidden City restoration is a traditional composite mortar based on the chemical reaction between pig blood protein and lime, with practical engineering effects such as enhanced bonding, improved moisture resistance, and crack resistance; this technique has been verified by modern materials science methods; it is currently being systematically organized and included in the White Paper on Export Technology for Chinese Ancient Building Restoration Materials; the relevant data will be used to support applications by Chinese ancient building restoration materials for EU CE certification and adaptation to U.S. ASTM standards, while also helping Chinese craftsman training services enter overseas heritage conservation supply chains.

Which niche sectors will be affected

Direct trading enterprises

As traditional restoration materials such as pig blood lime mortar are included in the export technology white paper, companies directly engaged in ancient building material exports need to respond to changes in target market access requirements. The impact is mainly reflected in: export declarations will need supplementary technical descriptions such as material composition, reaction mechanisms, and durability testing; clear reference criteria for the “adaptation of Chinese techniques” within CE or ASTM compliance pathways have appeared for the first time, although mandatory standard clauses have not yet been formed.

Raw material procurement enterprises

As a key bio-based raw material, pig blood’s stable supply, grading standards, and traceability may become focal points in subsequent supporting requirements of the technical white paper. The impact is mainly reflected in: there is currently no unified industrial-grade specification for pig blood protein extraction, and the batch stability of raw materials has not yet been incorporated into the existing building materials quality control system; if the export white paper later refines traceability guidelines for raw materials, it will drive upstream slaughter by-product processing enterprises to establish protein purification and quality control processes suitable for building material applications.

Processing and manufacturing enterprises

Manufacturers producing traditional mortar products are facing an upgrade in product definition: shifting from “antique-style building materials” to “validated functional restoration materials.” The impact is mainly reflected in: the need to cooperate in carrying out third-party testing of material properties (such as water absorption, salt crystallization resistance, and interfacial bond strength); some enterprises may need to adjust mix ratio parameters to match the process ranges recommended in the white paper, rather than relying solely on master craftsmen’s experience.

Supply chain service enterprises

Institutions providing integrated Chinese restoration technical services for overseas heritage projects are seeing their service offerings evolve from “labor export” to packaged solutions of “technology + materials + standards.” The impact is mainly reflected in: international project bids will require the simultaneous provision of material compliance statements, process validation reports, and training delivery records; the weight of technical appendices in service contracts is increasing, placing new demands on service providers’ standards conversion capabilities.

What key points should relevant enterprises or practitioners pay attention to, and how should they respond at present

Pay attention to subsequent official wording or policy changes

At present, the White Paper on Export Technology for Chinese Ancient Building Restoration Materials is still in the drafting or early release stage, and the full text has not yet been made public. Enterprises should continue tracking supporting documents issued by the National Cultural Heritage Administration, the Ministry of Commerce, and the China Association for Engineering Construction Standardization, with focus on whether the scope of application for techniques such as pig blood lime mortar is clearly defined (for example, limited to brick-and-timber structure restoration), what standards are cited for testing methods (for example, whether GB/T or ISO methods are specified), and whether transitional arrangements are established.

Pay attention to changes in key categories, key markets, or key business links

Give priority to reviewing product categories that are close to the “bio-based-inorganic composite mortar” technical pathway within your own portfolio (such as tung oil ash and derivative models of glutinous rice mortar), and assess whether they may be included in the subsequent expanded list of the white paper; meanwhile, study the growing demand in EU cultural heritage restoration tenders for the “modern validation of traditional materials,” especially paying attention to preliminary technical consulting content for projects in countries with large stocks of brick-and-timber heritage, such as Germany, Italy, and Poland.

Distinguish between policy signals and actual business implementation

The compilation of this white paper is a technical support action and does not mean that corresponding new items have already been added to CE or ASTM standards. Enterprises should not immediately launch full certification investment, but should first complete basic performance testing of core materials (for example, designing test plans by analogy with the dry-mixed plastering mortar logic in GB/T 25181—2019 Premixed Mortar), accumulate internal data, and then connect with third-party certification bodies after the white paper clearly specifies the referenced standards.

Prepare procurement, supply chain, communication, or contingency plans in advance

Enterprises involving biological raw materials such as pig blood may start small-batch stable supply tests, recording fluctuations in protein content from pig blood of different sources and differences in the final setting time of mortar; technical service teams serving overseas clients should organize existing process description documents and reconstruct their presentation logic around four elements—“material composition—reaction principle—measured performance—application scenario”—to avoid relying on non-quantified expressions such as “traditional wisdom” and “ancestral formula.”

Editorial Viewpoint / Industry Observation

From an industry perspective, the Palace Museum’s scientific interpretation of pig blood lime mortar this time is better understood as a “key preparatory step before building a standards interface,” rather than an immediately effective passport for market access. Observationally, its core value lies in translating traditional techniques into technical language that can be measured, reproduced, and compared for the first time, filling a methodological gap in connecting Chinese restoration materials with international standard systems. Analysis shows that current progress is still concentrated in the stages of data collection and document drafting, and has not yet entered mutual standard recognition negotiations or the trust-acceptance stage of certification bodies; the industry needs to continue monitoring whether the white paper will subsequently be linked to specific lists of testing institutions and whether a pilot mechanism for enterprise participation in validation will be established. This means that at this stage it is a strong signal, but not yet a breakthrough in terms of results.

The industry significance of the Palace Museum’s clarification of the pig blood lime mortar technique lies in promoting ancient building restoration from being “culture-narrative-led” to being “performance-data-driven.” It does not change the traditional technique itself, but it changes the way the outside world—especially international buyers and regulators—understands, accepts, and adopts such materials. At present, it is more appropriate to understand this as: China’s ancient building restoration industry is attempting to build a technical expression system that combines cultural authenticity with international applicability, and materials science validation is the first practical support point within it.

Information source note:
Main source: public content from the new book by Palace Museum expert Zhou Qian (released on April 23, 2024);
Items requiring continued observation: the official release time of the White Paper on Export Technology for Chinese Ancient Building Restoration Materials, progress in acceptance of this white paper by CE/ASTM standards organizations, and the issuance of supporting testing methods and detailed raw material specifications.