Materials

«In situ» measurements of surface wavevelocityon two prototype concrete slabs indicate that seismic measurements offer a reliable alternative to con-ventional penetration resistance and cylinder com-pression tests for determining the stiffness of Port-land cement concrete during curing. The surfacewave velocity was determined using a nondestruc-tiveand nonintrusive technique called the SpectralAnalysis of...

When roller-compacted concrete pavements (ReePi :11' u-cd ill Sweden, they are always used as a wear cour-e. Evpenenee shows that RCCP which have been laid meet the functional requirements. Carefully executed quality control is important for the results. Consequently two new lest methods. the Kango (cube) and the RA methods....

Aggregates from crushed road concrete were tried in 7 test sections, and 84 samples from some lOcrushing plants were :ested in the laboratory. lt has been shown that aggregates suitable for re-use in sub-Jases or road bases can be produced not only in fixed plants butalso by small mobile crushers,...

A stretch of the slip-road between the Al and A2 (Fiano tomano-S. Casareo) has been made of PCP (polyfunctional .omposite pavement). The system is "composite" owing to the rresence of several layers: mix cemented to cement binder, :ontinuous reinforcement concrete slab and bituminous layer; 'polyfunctional" owing to the diverse functions...

Roller-compacted concrete (ReC) offers a solution to the vast number of good quality lowvolume roads which will have to be provided in the near future to accommodate South Africa's rapidly expanding rural road needs. The research effort presented in this paper involved a laboratory study and the construction and accelerated...

Recyclingmaterials and industrial by-products are suitable for building purposes if the constructions made of them adequately withstand all loads occuring during the scheduled period of utilization and if they do not affect the environment unac-ceptably. Therefore the evaluation of recycling-and secondary materials must cover both the cons-tructional and the ecological...

In areas with a low bearing capacity of the soil it is very hard nd expensive to manage and maintain the road system. In eneral the common pavement structures are not able to resist uring its lifetime the deformation of the subsoil caused by the eavy weight of pavement structures....

lith the aim to verify the suitability of the different materials sed in marking roads for concrete pavements, more than 30 ommercial products were tested on the experimental field. Iaterials were of different nature: based on alkyd resins, vinyl .sins, alkyd-chlorinated rubber, chlorinated rubber, acrylic sins, etc. efore the application,...

This work reports the results obtained with the three point bend tests (TPBT) carried out on beams made up of the concrete used for the construction of a by-pass highway and, by comparison, of medium (50 N/mm2) and high strength (98 N/mm 2) laboratory concretes. Typical parameters of fracture mechanics,...

irnestone and emery sands divided into 6 fractions, were used ,cast cement mortar specimens in PSV moulds. After 28-day ater curing the specimens were subjected to accelerated ilishing and their Skid Resistance Value (SRV) was measured ith the pendulum tester. Specimens of 100 % limestone or )0 % emery sand,...

Concrete made with a superplasticiser has been used in Germany in the field of paving since the middle of the seventies. If these concretes of high workability show a high strength at a young age, they are called high early strength. These concretes can be subjected to high loading on...

Closing ceremony from 5th International Symposium on Concrete Roads 1986 Aachen Germany