Ube Industries Obtains Construction Technology Inspection Certification for Z-Sand,an Artificial Sand Made from Fly Ash

-"Stamp of Approval" for Commercial Operations-

February 7, 2005

TOKYO, February 7, 2005__ Ube Industries,Ltd., obtained Construction Technology Inspection Certification on November 5, 2004 for its product, Z-Sand, an artificial soil reinforcement material made using fly ash. The Certification, granted by the Public Works Research Center, recognizes excellent civil engineering materials, products, and technologies. It was awarded to Ube Industries and its partners, Electric Power Development Co., Ltd. (J-Power) and Taisei Corporation, and officially presented on February 7, 2005.

After examination and approval by the Center's Inspection Certification Committee, a group of experts from government, academia, and research institutions, the Certification was granted in recognition of the high performance and quality of Z-Sand as an artificial soil reinforcement material. Having obtained the Certification, Ube Industries will now actively market Z-Sand as a high-performance recycled product for application as a civil engineering and construction material, primarily to the national and local governments.

Z-Sand, in development at Ube Industries since 1995, is a granulated artificial soil reinforcement material made from fly ash, which is generated in coal-fueled electrical power stations. Z-Sand exhibits the same level of quality and handling performance as natural sandy soil.

The company is promoting the use of Z-Sand for backfill or refill under roadbed and road surfaces (embankments), and other structures, and also for river levees and land forming operations. The company emphasizes Z-Sand's contribution to environmental conservation, as an effective conversion of fly ash into a valuable resource, and as an artificial soil reinforcement material that can be substituted for natural sandy soil.

Characteristics of Z-Sand as a soil reinforcement material are as follows:

  1. Physical characteristics
    Possesses a granular distribution similar to sandy soil, and is lighter than ordinary soil reinforcement material, with better water permeability.
  2. Strength and support characteristics
    Possesses strength and support characteristics that are fully adequate for use as a soil reinforcement material.
  3. Implementation
    Can be implemented using existing implementation methods and construction equipment.
  4. Safe for the environment
    Meets soil environmental standards.
  5. Stability
    Properties of the material change very little over time, and it is safe for the environment over the long term.

In fiscal 2001, Ube Industries signed an agreement for Z-Sand production to take place as part of operations at the Waste Material Recycling Demonstration Plant of the Clean Japan Center, which is capable of handling up to 50,000 tons of fly ash per year. Pilot production and development of possible applications began in fiscal 2002 at the Okinoyama Coal Center, Ube City, Yamaguchi Prefecture, and ran for a two-year period. Upon successful completion of this pilot period, the facility commenced commercial operations on April 1, 2004. Z-Sand also obtained certification as a Yamaguchi Prefecture Recycled Product in fiscal 2002.

To date, Z-Sand has been implemented in more than 30 public works and other projects, and has won high acclaim for its physical characteristics as a soil reinforcement material, strength and support characteristics, ease of implementation, and environmental stability.

Ube Industries plans to develop the market through targeted sales for public works projects, marketing Z-Sand as a low-cost recycled product that meets soil environment standards. Sales volume is expected to reach about 80,000 tons in fiscal 2007.


  1. The Construction Technology Inspection Certification Program of the Public Works Research Center aims to incorporate new technologies resulting from private-sector R&D into construction projects, and to improve construction technology standards. At the Center, a committee composed of authoritative, experienced academics performs technology examinations, prepares reports containing details of the results of their inspections, and disseminates them to the relevant institutions. The Certification awarded to Z-Sand represents public recognition of its performance and quality, and widespread use of the new technology can be expected. The Construction Technology Inspection Certification Program is being implemented by the Association for Construction Technology Inspection Certification, a group of 14 public entities that includes the Public Works Research Center.
  2. About 9.2 million tons of fly ash was generated in Japan in fiscal 2002 (according to statistics by the Center for Coal Utilization, Japan), and this amount is expected to increase in the future. Of the total amount, about 85% (about 7.7 million tons) is now usable, while about 15% (about 1.5 million tons) is buried for disposal. About 80% of the effectively usable amount (about 6.1 million tons) is already utilized in the cement industry, so other civil engineering sectors are expected to increase their utilization to boost the overall recycling rate.
  3. Overview of Z-Sand
  4. Main application Used in civil engineering projects, as a substitute material for natural sandy soil (saprolite sandy soil or other sandy soil). It is used for backfill or refill under roadbed and road surfaces (embankments), and other structures, and also for river levees and land forming operations.
    Composition The main ingredients are fly ash, cement and other inorganic substances serving as hardening agents, and water. The fly ash powder is weighed, and then water is added in a batch granulator to promote granulation. After granulation, the mixture is cured for one to two days indoors, and then stored outdoors. The finished product consists of gray granules averaging one millimeter in diameter.
    Features - Low-cost manufacture due to the low cost of raw materials and the simplicity of the manufacturing process.
    - Can be handled in the same way as a natural material (outdoor storage is acceptable).
    - Uses a technology that prevents leaching of minute amounts of metals contained in the fly ash, for a product that is safe for the environment.


  • Coal Division
  • E&E Technology Center
  • Energy and Environment Division
  • Ube Industries,Ltd.
  • 1980, Okinoyama, Kogushi, Ube, Yamaguchi, Japan 755-8633
  • Phone : +81(836)31-6549
For inquiries please contact
  • Ube Industries, Ltd.
  • General Affairs & Public Relations Group
  • Seavans North Building, 1-2-1 Shibaura, Minato-ku, Tokyo 105-8449
  • Phone : +81-3-5419-6110
  • Contact us by Internet.