Building Masonry Stone
1Key Takeaways
This document specifies the classification, grading and marking, technical requirements, test methods, inspection rules, and requirements for identification, packaging, transportation, and storage of building masonry stone. It applies to natural stone used for masonry in buildings; natural stone of similar purpose may …
2Expert Interpretation
This in-depth analysis of the JC/T XXXX "Building Stone" industry standard covers the classification and marking of granulated stone, rubble, and stone blocks, as well as dimensional deviations, appearance quality, physical and chemical performance technical requirements, and testing methods, providing professional guidance for stone production and application.
In-depth interpretation of the JC/T XXXX standard for masonry stone
With the rapid development of green buildings and prefabricated buildings, the demand for standardized and regulated application of natural stone, as an important masonry material, is becoming increasingly urgent. JC/T XXXX, "Masonry Stone for Building," is the first building materials industry standard in my country specifically formulated for masonry stone, filling a standardization gap in this field and playing a significant role in regulating stone production, ensuring project quality, and promoting technological progress in the industry. This document was drafted by the National Stone Standardization Technical Committee (SAC/TC460) and other units, including Guizhou Jade Mining Investment and Development Co., Ltd., reflecting a standardization work approach that combines production, learning, and research.
Background and Technological Evolution Analysis of the Standard
For a long time, my country has lacked unified technical standards for building stone, resulting in uneven production and application levels across regions and frequent hidden quality problems in projects. Traditional masonry stone production relies heavily on experience and lacks a scientific classification system, performance indicators, and testing methods.
Based on a thorough survey of the current status of stone applications both domestically and internationally, and referencing fundamental standards such as GB/T 13890 "Natural Stone Terminology" and GB/T 17670 "Unified Numbering of Natural Stone," this standard, combined with the new performance requirements of modern architecture, is the first to systematically construct a technical standard system for masonry stone used in construction.In terms of technological evolution, the greatest innovation of this standard lies in the introduction of a new product category: stone blocks. Unlike traditional quartz stone and rubble stone, stone blocks are prefabricated components assembled from multiple stone parts using mortise and tenon joints or other connection methods. They are suitable for wall projects that integrate masonry and decoration, reflecting the impact of prefabricated building technology on the stone industry. Furthermore, the standard subdivides surfaces into four categories based on surface finishing precision: rough, matte, mirror, and natural, meeting the needs of different architectural styles and functions.
Analysis of Product Classification, Grading and Marking System
Chapter 4 of the standard establishes a scientific product classification, grading and marking system, which is one of the core frameworks of the standard.
4.1 Product Classification
According to product type, it is divided into: **Raw Stone (code SS)**, **Rough Stone (code RS)**, and **Stone Blocks (code AS)**. **Raw Stone** refers to regular hexahedral stones processed from rough stones; **Rough Stone** refers to irregular small stones that are unprocessed or partially processed; **Stone Blocks** are prefabricated components assembled through connection methods. This classification covers both traditional masonry stone and new prefabricated components, reflecting the standard's inclusiveness and forward-looking nature.
According to surface finish, it is divided into: Rough (CM), Matte (YG), Mirror (JM), and Natural (ZR).
Rough surfaces include flamed, water-sprayed, and bush-hammered finishes; matte surfaces refer to finely polished surfaces with low-level grinding; mirror surfaces are polished surfaces; and natural surfaces are unprocessed, natural surfaces. Different surface treatments not only affect aesthetics but also relate to the difficulty of controlling dimensional deviations and the selection of construction techniques. 4.2 Grading Based on dimensional deviations, stone is divided into two grades, A and B, with grade A having stricter requirements. This grading provides a clear quality gradient for both suppliers and buyers, facilitating selection based on needs and economic optimization. 4.3 Marking Rules The marking order is: stone name (according to GB/T 17670), product type, specifications, grade, and standard number. Example: Guizhou Zhenfeng wood grain stone (M5251) processed into stone blocks with an outer dimension of 900mm×600mm×60mm, matte finish, grade A, is marked as: M5251 AS 900×600×60 YG A JC/T XXXX—XXXX. This marking system achieves standardized transmission of product information.Technical Requirements Comparison Analysis and Implementation Points
5.1 Dimensional Deviation Requirements
Table 1 specifies the dimensional deviations for raw stone and stone blocks. For rubble stone, the deviation values are negotiated between the supplier and the buyer. The deviation values are set differently based on the type of measured surface (fine/mirror finish, rough finish) and grade (A, B), reflecting a balance between processing accuracy and cost control.
| Measurement Items | Surface Type Combination | Class A Deviation (mm) | Class B Deviation (mm) | Technical Points |
|---|---|---|---|---|
| Length and Width Deviation | Between Two Fine or Mirror Surfaces | ±3 | ±5 | High-Precision Machining Requirements |
| Between Fine/Mirror Surfaces and Rough Surfaces | ±5 | ±8 | Mixed Surface Control | |
| Between Two Rough Surfaces | ±8 | ±10 | Rough Machining Allowable Range | |
| Decorative Surface Flatness Tolerance | Fine Surface or Mirror Surface | 2.0 | 3.0 | Key Flatness Indicators |
| Rough Surface | 3.0 | 5.0 | Relaxed Requirements for Rough Surface |
Implementation Points: Manufacturing enterprises need to adjust the processing technology according to the product grade and surface type. CNC machining equipment is recommended for Grade A products, while traditional processes can be used for Grade B products, but process inspection needs to be strengthened. For **stone blocks**, the dimensional accuracy of the joints directly affects the assembly quality and should be a key control point.
5.2 Appearance Quality Requirements
Table 2 specifies the appearance defect limits for masonry stones with integrated masonry and decoration functions. Core requirements include: cracks exceeding 10mm in length are not allowed; two chipped edges or corners are allowed per meter of perimeter (minor defects are not counted); the number of color spots allowed per block is limited. For masonry stones used solely for masonry and structural functions, the appearance quality can be negotiated, reflecting functionally oriented differentiated requirements.
Practical Application Case: A historical and cultural district restoration project required masonry stones to have both structural function and maintain a rustic appearance. According to standard 5.2.2, the supplier and the buyer negotiated and determined a special appearance standard allowing a certain number of weathering marks and color differences, ensuring both structural safety and meeting the requirements for stylistic harmony.
5.3 Technical Requirements for Physical and Chemical Properties
Table 3 specifies the physical performance indicators for five types of stone: granite, marble, limestone, sandstone, and slate. This is another core part of the standard.
| Performance Indicators | Granite | Marble | Limestone | Sandstone | Slate | Technical Significance |
|---|---|---|---|---|---|---|
| Water Absorption/% ≤ | 0.60 | 0.50 | 3.00 | 8.00 | 0.25 | Basic Weather Resistance and Frost Resistance |
| Dry Compressive Strength/MPa ≥ | 100 | 50 | 30 | 20 | 40 | Key Indicators of Load-Bearing Capacity |
| Dry Bending Strength/MPa ≥ | 8.0 | 7.0 | 4.0 | 3.0 | 20.0 | Bending Performance, Important for Thin Plates |
| Softening Coefficient ≥ | **General Walls:** 0.75; Walls over 50 years old: 0.85; Load-bearing walls in damp/freeze-thaw/chemical environments: 0.90. **Water Softening Resistance:** The softening coefficient refers to the ratio of compressive strength in a water-saturated state to that in a dry state, reflecting the stone's ability to retain strength under water. The standard is based on the wall's design life and usage environment classification requirements, embodying the concept of full life-cycle quality. **Freeze-Thaw Resistance:** The requirement is a strength retention rate of ≥80% after freeze-thaw cycles, applicable only to areas with freezing temperatures, a reasonable provision based on my country's diverse climate. **Radioactivity Requirements:** Natural granite masonry stones must comply with GB6566 requirements for main building materials; this is an important clause ensuring indoor environmental safety.
Guidelines for the Implementation of Test Methods and Inspection Rules6.1 Test Methods for Dimensional DeviationsThe standard specifies the measurement locations and methods in detail: length and width are measured at three locations on the decorative surface (see Figure 2), and height is measured along the centerlines of the four sides (see Figure 3). Flatness is measured using a 1000mm steel straightedge and feeler gauge, and diagonal difference is measured using a steel ruler. These methods ensure the consistency and comparability of measurements. Implementation Recommendations: Manufacturing enterprises should establish standardized measurement stations, equipped with measuring tools such as steel rulers, steel straightedges, and feeler gauges that meet the required accuracy, and calibrate them regularly. For large stone blocks, a dedicated measuring stand needs to be designed to ensure measurement stability. 6.2 Appearance Quality Inspection MethodIn a well-lit area, visually inspect the color and pattern of the sample from a distance of 2m, and use a vernier caliper with an accuracy of 0.02mm to check for defects. This combined subjective and objective inspection method ensures both efficiency and accuracy. 6.3 Physicochemical Performance Test MethodAll performance tests adopt the current national standard methods, ensuring the authority and consistency of the methods. Special note: The compressive strength, flexural strength, softening coefficient, and frost resistance test specimens are all 70mm×70mm×70mm cubes. This standardizes the specimen specifications, facilitates comparison, and data accumulation. 7.1 Factory Inspection and 7.2 Type InspectionThe factory inspection items are dimensional deviations and appearance quality, which are the basis for ensuring batch quality consistency. The type inspection includes all technical requirements and is conducted when a new factory is put into production, when there are major changes in the process, annually, or when required by quality supervision. Table 4, the sampling judgment table, adopts an attribute sampling scheme, determining the sample size, acceptance number (Ac), and rejection number (Re) based on the batch size. For example, for a batch of 26-50 pieces, 8 pieces are sampled; ≤1 rejection is acceptable, ≥2 rejections are unacceptable. This scheme balances inspection costs and quality risks. Table 5 specifies the sample specifications, quantity, and methods for various performance tests. During implementation, note that samples should be taken from the slabs according to regulations to avoid corner effects; radioactive samples require 2kg of irregularly shaped samples and should represent the radioactivity level of the entire batch of stone. Chapter 8 specifies the technical requirements for product circulation, which are crucial for ensuring the final quality of the product. Marking Requirements: In addition to the packaging and storage pictorial markings specified in GB/T191, each masonry stone should be marked according to Chapter 4; branded stones should have their trademarks affixed. For installations requiring a specific sequence, the sequence number must be clearly marked. This is especially important for the on-site assembly of stone blocks. Packaging Requirements: Pack separately according to type, specification, grade, and color, with smooth surfaces facing each other and padded. Wooden railings or pallets must have corner and edge protectors. Waterproofing and moisture-proofing measures are essential, especially when using packaging materials that are easily contaminated by moisture. Exported wooden packaging must undergo fumigation treatment to meet international trade requirements. Transportation Requirements: Protect from collisions and rolling. Special protection is required for easily damaged mirror surfaces and stone block joints. Storage Requirements: Indoor storage is recommended; outdoor storage requires covering and protection. Categorizing and stacking by type, specification, grade, installation location, and color is not only a quality assurance measure but also improves warehousing and construction efficiency.
Standard Implementation Recommendations and Industry Impact OutlookImplementation Recommendations for Manufacturing Enterprises1. **Establish a Standardized Production System:** Optimize production processes, especially dimensional accuracy control, based on product classification and grade requirements. Invest in necessary processing and testing equipment, such as CNC cutting machines, automatic grinding machines, and coordinate measuring machines. 2. **Strengthen Raw Material Quality Control:** Raw material selection should meet physical and chemical performance requirements. Establish a raw material performance database to achieve material selection based on performance and processing based on intended use. 3. **Improve Inspection and Testing Capabilities:** Establish an enterprise laboratory equipped with pressure testing machines, bending testing machines, water absorption rate measuring devices, and radioactivity detectors, etc., to conduct factory inspections and type tests according to standard requirements. 4. **Developing New Products:** Focus on the research and development and production of stone blocks, studying connection structure optimization and prefabrication technology to meet the needs of prefabricated buildings.Design, Construction, and Application Recommendations 1. **Standardized Design and Material Selection:** Select appropriate stone types and grades based on building function, environmental conditions, and design life. Granite should be prioritized for load-bearing walls, while marble and sandstone can be used for decorative walls. 2. **Strict On-Site Acceptance:** Verify product quality certificates according to standard inspection rules and conduct sampling inspections of key indicators. For stone blocks, the matching accuracy of connecting components should also be checked. 3. **Optimizing Construction Techniques:** Different surface types of masonry stones should be constructed using appropriate masonry methods and grouting techniques. For mirror-finish and matte surfaces, construction pollution must be prevented; for rough and natural surfaces, attention must be paid to the flatness of the masonry. Industry Impact and Development Prospects The implementation of this standard will promote the transformation of the masonry stone industry from experience-based to technology-based, fostering the following developments: 1. **Product Quality Improvement:** Unified technical requirements will eliminate outdated production processes and promote the overall improvement of the industry's quality level. 2. **Industrial Structure Optimization:** Standardization will promote specialized division of labor, forming a complete industrial chain encompassing raw material mining, stone processing, prefabrication of stone blocks, and construction and installation. 3. **Accelerated Technological Innovation:** Focusing on technical challenges such as dimensional accuracy control, connection structure optimization, and performance improvement, a number of new technologies, processes, and equipment will emerge. 4. **Expanding Application Areas:** Standardized masonry stones will be more widely used in areas such as historical building restoration, characteristic town construction, landscaping, and green building. As the first industry standard to be formulated, JC/T XXXX "Masonry Stones for Building Use" may require continuous improvement based on feedback during implementation. It is recommended that industry associations organize standard dissemination and training, compile application guidelines, establish a database of typical cases, and promote the effective implementation of the standard. Meanwhile, we will pay close attention to the development of international stone standards, conduct benchmarking studies as needed, and enhance the international influence of my country's stone standards. In short, this standard is not only a technical specification but also a catalyst for the industry's transformation and upgrading. Through its full implementation, it will undoubtedly propel my country's masonry stone industry into a new stage of standardized, high-quality, and sustainable development.3Version History
JC/T 2902-2025
2025-08-19
5Citation Network0
Cite this standard
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Referenced herein
Referenced by JC/T 2902-2025
GB 6566
GB/T 13890
GB/T 17670
GB/T 18600
GB/T 191
GB/T 9966.1
GB/T 9966.2
GB/T 9966.3
6Frequently Asked QuestionsWhat is JC/T 2902-2025?
JC/T 2902-2025 — Building Masonry Stone is an international standard developed by Professional Standard - Building Materials. This document specifies the classification, grading and marking, technical requirements, test methods, inspection rules, and requirements for identification, packaging, transportation, and storage of building masonry stone. It applies to natural...
What does JC/T 2902-2025 cover?
This standard covers: This document specifies the classification, grading and marking, technical requirements, test methods, inspection rules, and requirements for identification, packaging, transportation, and storage of building masonry stone. It applies to natural stone used for masonry in buildings; natural stone of...
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The current published version is JC/T 2902-2025, published on 2025-08-19. Always check for amendments or pending revisions.
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