The main goal of curing is to protect the young concrete against drying out. These investigations indicate, that concrete temperatures during the first day of hardening are decisive for the magnitude of thermal stresses of the hardened concrete and the related cracking risk. High thermal tensile stresses occur, if the...
Influence of Cement on the Durability of Concrete Pavements
Cement for concrete pavements has to meet special requirements. Besides cement properties which influence the fresh concrete, the cement is of great importance for the durability of concrete pavements. If the joints in the young concrete are not sawn early after paving, cracks can form in the pavement. With cracking-frame...
Fine-Grained (Sand) Concrete for the Construction of Cement Concrete Road and Airfield Pavements
The problem of using fine-grained (sand) concrete instead of the "classic one in the construction of road and airfield pavements is analysed. In sand concrete the coarse aggregate, crushed stone or gravel, are substituted by natural sand or a blend of natural sand and screenings 0.5 (10) mm. The use...
Factors Affecting the Abrasion Wear of Concrete Pavements
This paper describes the application of a relatively simple and inexpensive laboratory test deiived Iiuiii ASTM procedure C779 for evaluating abrasion resistance of concrete surfaces. Factors affecting the reproducibility and precision of the test are quantified. The paper describes the use of the test to evaluate trial mixes of paving...
Reuse of Alkali Damaged Road Concrete in Cement Bound Road Bases
Aggregates were obtained from an alkali-silica damaged concrete road slab aggregates and used for road base concrete with different kinds of cement (low alkali cement, high alkali cement). After analysing the samples produced with these mixes, which were exposed for up to one year to different hardening conditions, no alkali-silika...
Mix Design for Concrete Pavements Durability Options Based on the New European and Italian Standards
The provisions of the European Prestandard ENV 206 "Concrete - Performance, Production, Placing and Compliance Criteria" place the accent on the qualitative requirements (physical, chemical and mechanical ones) of a durable road concrete. The theoretical life of a rigid road pavement obviously r1.pends on the design and the quality control...
A New Assortment of Cement (CD 40-A) Meant for Concretes for Roads, Motorways and Airport Runways
The use of CD 40-A cement eliminates the classical procedures of measuring plastifying and air entraining additives at the preparation on site of the road concrete. The article presents the main characteristics of CD 40-A and the results of laboratory tests carried out to establish the influence of this type...
Freeze-Thaw Damage to Concrete Pavements
Requirements for concretes in colder environments are stricter than those normally requested for standard commercial concretes. Therefore, a concrete produced with (i) high quality ingredients, (ii) a water/cement ratio of 0.35 to 0.40 by mass, (iii) 3.0 to 6.0 percent entrained air, (iv) an adequate maturity, i.e. when the compressive...
Experiences with the Treatment of some Defects of a Concrete Pavement during Construction
The aim of this paper is to discuss some defects of the concrete pavement during the construction of the second northern expressway project in Taiwan. The possible reasons of and techniques for repairing these defects are studied in the paper. The defects discussed include the cracks in the lean concrete...
Evaluation of the Reliability of Concrete Pavements Considering the Fatigue Properties
In the mechanistic design method of concrete pavements, the flexural fatigue properties have a great influence when analysing the design life. Accordingly, the purpose of this study is to clarify the effects of stress ratio (YmIn/cmax), maximum size of coarse aggregate and static flexural strength of the pavement concrete on...
Technological Aspects of Ensuring the Frost and Salt Resistance of Concrete Pavements
The resistance of concrete pavements against frost and salt is ensured by creating the necessary volume of finely-dispersed air voids in the concrete by entraining air during the mixing process with appropriate admixtures. The influence of various structural and technological factors on the stability of entrained air and the formation...
Technique to Create Wear Resistant Concrete
Through expericnccs during the last years we have gained knowledge about the decisive factors to obtain a wear resistant concrete pavement. The most important factors are: the quality of the aggregate, the strength of the concrete, the adhesiveness between the cement paste and the aggregate particles, the maximum size of...