Materials

Seven experimental sections of thin overlay construction on old concrete and asphalt road pavements have been built in Belgium since 1982. These comprise a total area of 107 000 m2 of fibre reinforced concrete (five sections) of la cm and 12 cm thickness and 34000 m2 of continuously reinforced concrete...

The incineration of household refuse in the Federal Republic of Germany yields up to about 3.5 million tonnes of residual waste per year. About 90% of this consists of grate ash and about 10% of fly-ash, the latter mostly being collected in electrostatic precipitators. The grate ash consists chiefly of...

Industrial by-products have long been used in French road construction. Experience gained over the last twenty years with che extensive use of by-product gravel-sand stabilized with hydraulic binders as a sub-base material, as well as the results of highway engineering practice in neighbouring countries like Germany and Belgi~prompted the LPC...

In che paper, results are presented of laboratory research and applications in practice of concrete and masonry waste as aggregates for concrete. In a thorough study the amounts, composicion and relevant properties of the waste were investigated. Based on the results of tests in the laboratory and of full scale,...

For environmental reasons, it is becoming increasingly difficult and eherefore expensive to find fresh sites for wasee disposal. Investigations have shown that coal fly-ash, refuse incinerator grate ash, demolished road asphalt and concrete rubble can, when suicably treated with cement, be economically reused for road construction, for which purpose they...

The replacement of traditional aggregates (limestone) by crushed blastfurnace slag or LD steelmaking slag in lean concrete and in cement-stabilized hardcore was investigated. The effect of adding fly-ash to mixes of the conventional type was also studied. For mixes of equal composition (in parts by volume) and equal grading (by...

A special session of the 65th annual meeting of the Transportation Research Board in Washington, in January 1986, brought together some 50 practitioners and research workers on the theme "Erosion of sub-bases; stepping of slabs and pumping of concrete pavements"; ~he presentation of 3 U.S. papers and two French ones...

A number of research projects relating to the cementbound sub-base (CBSB) are currently in progress in the Federal Republic of Germany. Their object is to develop an optimized technological approach with a view to further improvement and even greater economy in the use of this well proven form of construction....

At Hamburg, sand-cement stabilization (SCS) conseructed by the central-mixed (stationary plant) method is successfully used for frose-protection courses. The requirements applicable to these courses, which as a rule are 15 em thick, are based on those for cementbound sub-bases as laid down in the TVT regulations: degree of compaction ~98%,...

The principal criteria applicable to the mix design and the properties of lean concrete are: - splitting tensile strength in the region of 1.7 MFa and compressive strength in the region of 15 MPa at 28 days; - good erosion resistance; - lowest possible modulus of deformation; - possibility of...

Cement-bound sub-bases (CaSBs) are constructed ~ithout joints. During and after hardening, cracks may be formed in consequence of drying and/or cooling, even if the sub-base has noc yet been subjected co any traffic load. It would be desirable to have no cracks or only very fine ones (capable of eransmieting...

The curing compounds hitherto employed have not always been found satisfactory when applied to road concrete with superplasticizer, to concrete on small jobs, to concrete placed by slipforming and to cement-boundsurfacings. For this reason three new types of curing compound have been introduced, namely, compounds which - give good protection...