Case studies of Advanced Construction and Demolition waste(CDW)
Recycling initiatives and technologies In JAPANAffiliation

RYOMA KITAGAKI,
The Associated General Contractors of Tokyo
Association of Building Demolition Contractors of Tokyo
Tokyo Industrial Waste AssociationLocation

Kita 10, Nishi 8, Kita-ku, Sapporo 060-0810, JAPAN

Position:

Associate Professor,
Faculty of Engineering, Division of Human Environmental Systems,
Building Engineering Laboratory, Hokkaido University (RYOMAKITAGAKI)

Name/Surname

RYOMA KITAGAKI
ryoma@eng.hokudai.ac.jp

e-mailTitle
Themeclassification

New quality management codes for low quality recycled
aggregate named "Tokyo brand ‘Cool eco-Stone’", extending
applicability for several soil/ground materials.
Prevention
Re-use〇Technology
development stage〇

RecycleReduce Co2Legacy
Business to overseas
Etc.
Practical use
Scheduled to be put into practical use by 2020
Scheduled to be put into practical use after 2020

Specific content-This code is a quality standard of recycled aggregate established by thecooperative committee among industries, local governments andacademia for branding recycled aggregates which have much attachedmortar.
This quality standard aims to be widely used not only for roadbedmaterials but also general geomaterials(ground materials).
.
-The characteristics of this code is to design the grades of concrete wastes
for applying embarkment, pervious foundations, and drainage systems
as well as conventional road base/subbase. As a result, the quality ofconcrete wastes become improved and connect into manufacturing highquality recycled materials applied to several soil structure.
Appeal point-this quality standard designed comprehensively for recycledgeomaterials(ground materials) made from concrete waste isunprecedented worldwide.
-Tokyo Metropolitan Government has also publicly certified this private
quality standard, and its recognition as a brand is increasing.
-Through creating a quality standard for recycled materials andestablishing the goal of setting up as a brand, we are proud that many
people have involved to improve the image of recycled materials and thecomprehensive framework has been created to contribute to promoting
recycling.

-21-

New quality management codes for low quality recycled aggregate named"Tokyo brand ‘Cool eco-Stone’", extending applicability for several
soil/ground materials.
1. Quality Management process for low quality recycled aggregate extending applicability to
several soil/ground materials.
Tokyo brand “Cool eco-Stone”, new codes for low quality recycled aggregate is assumed to be
designed for extending applicability to several types of geomaterials as well as recycled crusher-run forroad base/subbase. Specifically, Tokyo brand “Cool eco-stone” is considered to satisfy the following two
requirements:① Sufficient mechanical performances required for geomaterial, such as embarkment, pervious
foundations, and drainage systems② Extreme low concentration of any harmful components such as chromium hexavalent, which
may cause critical adverse environmental changes in the ground.
In order to satisfy these requirements of “Tokyo brand ‘Cool eco-stone’’’, the special committee
consisting of all stakeholders, such as related industries, local governments and academia, establishedthe codes for quality management system in close cooperation.
According to these codes, the comprehensive quality management system covering from concrete
wastes generated in demolition sites to recycled aggregate applied in construction sites are standardized
accurately. These codes include the rating system of quality of concrete wastes qualifying into A, B, andC. In consequence, the rating system succeeds the improvement of the quality of recycle aggregate,because the cost for controlling quality of recycled aggregates would be decreased and the quality
consistency in manufacturing recycled aggregate would be improved with low cost. It is a simple but aninnovative system to progress recycling concrete wastes.

2. Performance of recycled aggregate applying as ground materials
Table 1 shows the standard (draft) for recycled aggregate named Tokyo brand “Cool eco-stone”.
This standard (draft) requires that recycled aggregate applying in ground proves environmental safety incompliance with the standard value of “Soil Contamination Countermeasures Act” based on the result ofleaching test (JIS K 0058-1) in the “as-is” use form and the results of contents test (JIS K 00580-2) , so
as that surrounding soil and groundwater might sustain environmental safety for a long time.
Additionally, the codes require to disclose several values for contributing to awareness of the quality
and recasting public images of recycled aggregates.

-22-Table-1 standards (draft) of recycled aggregate for applying as geomaterials
Names of recycled Conventional
aggregatesrecycled
crusher-run

RC-40
For roadbed

RS-40
RC-40
RC-40
gravel For back-filling
For infiltration For
trenchcompaction

Construction
Roadbedmethod applying construction
each product

Roadbedconstruction

Permeability
methodFoundation
improvement
work

Earthwork

Roadbedmaterial

Infiltration
trench material

Gravelcompaction

Backfillingmaterial

Standardsof Roadbedof test methods Function
for each item
recycled aggregate material

Items forquality management

Regulations
on harmful component content

Heavy
metal JIS0058-1 or JIS0058-2
elution/ content－

Based on the following two test results
1. To satisfy the dissolution amount criteria (Type 2 SpecifiedHazardous Substance) of Soil Contamination Countermeasures Actby dissolution test(JISK0058-1) on appearance sample
2. To satisfy the content criteria (Type 2 Specified HazardousSubstance) of Soil Contamination Countermeasures Act in contenttest(JISK0058-2) of crushed sample

Chloridecontent

JISA5023A4.7－

0.04wt%Ph

JGS0211－Disclose data

Electricalconductivity

JGS0212－

200mS/m or lessIgnition loss

JISA1226－

10% or lessAsbestoscontent

JISA1481-1－Do not detect

Impurity
contamination
rate

JISA5023A4.2

To satisfy the civil engineering material specification(edited by Construction Bureau ,Tokyo Metropolitan Government)Grainsize JISA1102
distribution－

To satisfy the civil engineering material specification(edited by Construction Bureau ,Tokyo Metropolitan Government)

Solidvolume JISA1104
percentage－

Disclose data

65%or lessDisclose dataFine
fraction JISA1223 or JISA1103
content－

less than 10%

2% or lessless than 10%

Water
absorption

JISA1110－

8.65% or less

7% or less

9.1% or less

8.65% or lessDensityabsolutely
condition

in JISA1110
dry－

2.05g/cm3 or
more

2.1g/cm3 or
more

2.03g/cm3 or
more

2.05g/cm3
Or moreDensitysaturatedsurface-drycondition

in JISA1110

Mass ofvolumeunit JISA1104

Percentage
wearof JISA1121－

Disclose data－

Disclose data
40% or less

Regulations on physical mechanics characteristics

Plasticity index JISA1205

6% or less-

6% or less－Disclose data

Plastic limit

JISA1205－

Disclose data

Liquid limit

JISA1205－

Disclose data

Cone index

JISA1228－Maximumdensity

dry JISA1210－

Disclose data

Optimummoisturecontent

JISA1210－

Disclose data

Modified CBR

JISA1211

40% or more－

Disclose data－

400KN/m3 or more

Disclose data

40% or more

Expansion ratio JISA1211－

3% or less

Methodof JGS0051
classification ofGeomaterials
for engineering－

Disclose data

Internal friction JGS0524
angle－

Cohesion

JGS0524－Slaking rate

NEXCO testing method110－

Disclose data

1% or lessHydraulicconductivity

JISA1218－

Disclose data

1x10-4 m/sec-23-

Disclose data

35degree or more
Disclose data