scope:

This Standard specifies the melt-solidified aggregate for concrete manufactured by melting the municipal solid waste, sewage sludge and their burned ashes at a temperature at least as high as 1200°C and cooling and solidifying them (hereafter referred to as molten slag aggregate).

The molten slag aggregate is an aggregate manufactured for the purpose of efficient utilization of the municipal solid waste, sewage sludge, etc. in their melt-solidifying facilities, and includes the following.

a) The molten slag aggregate produced in private melt-solidifying facilities which are entrusted by the municipal authorities to treat municipal solid waste, or that produced when municipal solid waste is treated together with industrial waste whose reuse is approved by the municipal authorities

b) The molten slag aggregate subjected to magnetic selection, particle size adjustment, etc. property modification in the melt-solidifying facilities or separate facilities

c) Slag manufactured from melting furnace fly ash, though not normally included in the molten slag aggregate, which has been produced in melt-solidifying facilities equipped with control system meeting the environmental safety quality criteria specified in 5.7.

The application of molten slag aggregate for concrete shall be as follows.

d) The molten slag aggregate can be used for concrete satisfying all of the conditions below.

1) Design standard strength of 35 N/mm² or lower.

2) Water-cement ratio of 55 % or smaller, for ensuring durability

However, the molten slag aggregate can be used for precast unreinforced concrete products specified in JIS A 5371 and precast reinforced concrete products specified in JIS A 5372 whose design standard strength is above 35 N/mm² , provided that the purchaser of the molten slag aggregate is familiar with the application conditions such as the characteristics of the precast concrete product, required strength and durability, and environment in which the product is to be placed, and also provided that the purchaser of the precast concrete product has specifically requested the use of the molten slag aggregate.

e) The molten slag aggregate cannot be used for the following.

1) Prestressed concrete for all applications (e.g. precast prestressed concrete specified in JIS A 5373, prestressed concrete to be installed on site, etc.)

2) Precast concrete used for buildings, more specifically for their foundation, principal structural parts and parts that are significant in terms of safety, fire prevention or hygiene.