‫ە‬Research trends and results

Developing environmental loadfactors for construction
materials used in social
infrastructure LCASONE Shinri, HeadTAKIMOTO Masamichi, Researcher KANDA Taro, Researcher
Road Environment Division, Environment Department

Research trends and results(Keywords) Life cycle assessment, environmental load factor, construction materials

1. BackgroundIf we are to introduce life cycle assessment (LCA)
into the development of social infrastructure, we willneed to establish a method of calculating
environmental load arising throughout all processes
from the extraction of resources to the manufacture,installation, commissioning, demolition and disposal ofmaterials. Since environmental load is calculated as thevolume of a material multiplied by its environmentalload factor, we will need to develop environmental loadfactors covering all construction materials and energies,etc., used when developing social infrastructure.
We have prepared environmental load factors
concerning CO2 emissions and others for both generalproducts and individual products. The aim is that theseshould enable construction industry operators tocompare ordinary products (ordinary construction
materials as pre-manufactured products) withindividual products (specific products produced byindividual factories and companies, special products),
and to choose materials with a lower load byintroducing LCA to social infrastructure.
2. Developing a list of environmental load factors
for ordinary products
We calculated the environmental load factors ofordinary products using a method that combines thesummation method with the input-output method. Thatis, we used the summation method to calculate loadfactors for “principal construction materials”, based on
official statistics and others from which physical data
can be obtained in categories of specific commodities.
For other items, we complemented this with theinput-output method. We selected steel, cement,asphalt blend, rubble, and others as elasticity markers
for “principal construction materials”1). We thencalculated their load factors and arranged them in a list(Fig. 1)2).
By complementing this with the input-output method,
we standardized system parameters (the range forcalculating environmental load) into a range based on
domestic economic activity. This enabled us tocalculate load factors for different materials under thesame conditions. For principal construction materials,
meanwhile, load factors can easily be updated byinputting the latest aggregated data.
3. Method of creating environmental load factors
for individual products
We calculate environmental load factors forindividual products using the summation method,which aggregates environmental load in individual
manufacturing processes. To do this, we need to set a
method of distributing system parameters andenvironmental loads common to materials. For
principal construction materials, we studied and setsystem parameter and environmental load distribution
methods, together with academics and professional
experts in the field of materials and the environment(Fig. 2)3).
Also, since the summation method involves anelement of discretion in setting system parameters, forloads other than those subject to aggregated calculation,
we made it possible to compare them with ordinary
products by adding sector input-output tables andheadings as “Estimates of unaggregated values”.
CO2 emissions load factor
Name of commodity
Freshly mixed concrete, ordinary
Freshly mixed concrete, earlystrength
Freshly mixed concrete, blastfurnace
Concrete products
Asphalt blend or mixture
Recycled asphalt blend or mixture
RubbleRecycled rubble

Unit

Total

Production

Shipment

Fuel usedm3m3
m3ttttt

Fig. 1 Example of commodities on an ordinary productenvironmental load factor list
CO2 emissions load factor
Name of commodity

Light oil
Blast furnace slag
Steel plate
Steel sheet pile
Portland cement, ordinary
Portland cement, earlystrength
Blast furnace cement
Fly ash cement

Unit

Total

Production

m3m3
m3ttttt

Fig. 2 Example of system parametersShipment

Fuel used‫ە‬Research trends and results

y System parameters of asphalt blend
Final disposal
siteConstruction site
Demolition,etc.

Transportation

This range is calculated as the environmental load throughout
the lifecycle of asphalt blendDisposal

CO2 (kg-CO2/t)
Stone quarry
Rubble

Item
Transportation

Power station

Product
manufactureusing newmaterials

Transportation

Electricpower

Oil refineryTransportation

Heavy oilTransportation

Asphalt

RecyclingQuantityElectric power

Load factor

Power consumption

Quarrying site A,(1)

Aggregate

Load factor

Light oil consumption

Oil refinery (3), (4)Asphalt

Load factor

Light oil consumption

Heavy oil

Load factor

Light oil consumption

Recycling plant
Transportation

Load factor

Equipment
usedElectric power (2)Commodity /Consumption
item

Construction site
Transportation

Product
manufactureusing recycledmaterials

Transportation

Product
acceptance

Installation

Demolition, etc.

Transportation

Disposal
Recycling plant

System parameters

Transportation

Disposal

4. Publication of results
The environmental load factors of construction
materials used in social infrastructure will first beexamined and verified by academic experts in the fieldsof materials and the environment, in a committee set up
within the Japan Society of Civil Engineers. They willthen be compiled into a Comprehensive TechnicalDevelopment Project Report.
References
1) M. Takimoto, S. Sone, H. Kishida, T. Fujita: Studyon screening of target commodities for an inventory
database used in social infrastructure, Environmental
System Research Papers, Vol. 38, pp. 203-211

Transportation

Recycling2) S. Sone, M. Takimoto, H. Kishida, T. Fujita:
Development of an inventory database used in social
infrastructure, 65th Annual Scientific Lecture Series
Lecture Summaries
3) T. Kanda, S. Sone, H. Kishida, K. Hanaki: On therationale of system parameters of materials inventory
data used in life cycle assessment of social
infrastructure, Environmental System Research Papers,
Vol. 38, pp. 185-191