HC Deb 11 January 1993 vol 216 cc516-7W
Mr. Stern

To ask the Secretary of State for Transport if he will make a statement on the extent to which blast furnace slag has been approved for use in motorway embankments.

Mr. Kenneth Carlisle

Blast furnace slag is approved in the Department's Specification for Highway Works for use as general fill, as selected granular fill and as a capping material in motorway embankments. A copy of the specification is in the Library.

Mr. Stern

To ask the Secretary of State for Transport what regulations govern the choice by contractors of the type of fill material for use in major road building projects.

Mr. Kenneth Carlisle

Contractors are required to satisfy the specification for each particular scheme. This specification incorporates the Department's Specification for Highway Works and lays down additional requirements as necessary including any environmental constraints.

Mr. Stern

To ask the Secretary of State for Transport if he will undertake and publish a comparative study of the costs of using(a) blast furnace slag and (b) freshly quarried stone as fill material for major road building projects.

Mr. Kenneth Carlisle

A study was carried out in 1991 by the Department of the Environment into the economics of using mineral and industrial waste materials as substitutes for naturally occurring aggregates. The study included a comparison of the costs of using steel blast furnace slag as a replacement for crushed rock. The report was published (ISBN 0 11 7524840) and a copy was placed in the House of Commons Library.