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Highly-flowable and self-compactable concretes (HFSCC) containing various types of powder materials were tested for their freezing and thawing resistance. The powder materials incorporated into the concrete include four kinds of cements, and two mineral admixtures that were used for replacing a part of normal portland cement. For most of concrete mixtures, water-to-powder materials ratio was fixed at 0.35 by weight, and a proper amount of viscosity-modifying admixture was added in them in addition to air-entraining and high-range water-reducing admixture. Concrete specimens were subjected to freezing and thawing test at the ages of 2 or 3 days, 14 days and 28 days. The results were analyzed utilizing a new technique proposed by one of the authors, with which the continued hydration of cementitious materials during the freezing and thawing test could be properly taken into account. It was found that the conventional procedures for determining the durability factor were not appropriate for young age concretes in which slowly hydrating cementitious materials were used. Another main conclusion was that the same precautions as those for ordinary concrete should be applied to the cold weather concreting of HFSCC, even when its water-cement ratio was as low as 0.35.

Frost damage of concrete gradually proceeds due to freezing and thawing of water in pore structure. The main cause is the expansion of frozen water, which is influenced by pore size distribution and air void spacing factor. This study focuses on the pore size distribution and the air void spacing factor. Freezing and thawing tests were conducted and the expansion was measured. Based on the test results, a strain model was proposed. Furthermore, the pore size distribution and the air void spacing factor were measured for different areas of an actual structure, and the degree of deterioration in the structures was compared with the expansion volume calculated using the model. It is found that the strain model represented the frost-resistance of concrete taking into account the difference of the pore size distribution and the air void spacing factor. That model also simulated the deterioration of an actual structure.

This report presents the results of laboratory studies conducted to determine freezing and thawing resistance of high flowing concrete. High flowing concretes were made using a combination of different cementitious materials (Fly ash, blast-furnace slag and silica fume). The water-to-cementitious materials ratio was 0.32, and the sand coarse aggregate ratio was 0.51. All mixtures used a superplasticizer and were non-air-entrained. Test cylinders were made for testing in compression at 1 , 7 and 28 days, and test prisms were cast for determining resistance to freezing and thawing cycles in accordance with ASTM C 666, Procedure A. The curing methods were water curing and steam curing. The air void parameters of the hardened concrete were determined on sawn sections. The pore size distributions of the hardened concrete was measured by mercury porosimeter. The test results have indicated that the non-air-entrained , high-flowing concrete with steam curing showed low durability factors. The high flowing concrete with the water curing performed satisfactorily when subjected to up to 900 cycles of freezing and thawing.

High Performance Concrete (HPC) has been developed primarily for its strength having a compressive strength in excess of 70 MPa, approximately double the strength of conventional concrete. The porosity of this type of concrete, especially when silica fume is added to the mix, much lower than conventional mixes. It is, therefore, assumed that high performance concrete provides significantly better protection against corrosion of reinforcing steel than conventional concrete, but this has not yet been substantiated. A field exposure program is underway with cast-in-place and pre-cast samples, containing embedded reinforcing steel probes exposed to pulp & paper industry effluent at two locations on Vancouver Island, B.C., Canada. The cast-in-place samples were loaded in three-point bending prior to exposure to initiate cracks in the location of the corrosion probes. Probes were also embedded in uncracked areas of the beams. One lower quality concrete, one industrial standard concrete, one HPC and one HPC containing silica fume were included in the test matrix. Parallel laboratory corrosion studies are being conducted on cast-in-place specimens exposed to a simulated effluent. The initial results of the field exposure showing the difference in corrosion protection of reinforcing steel in the four different types of concrete subjected to accelerated curing and conventionally cured are presented. Laboratory results investigating the effect of cracking on the corrosion protection provided by the four types of concrete are also presented. The reinforcing steel corrosion was evaluated using linear polarization resistance (LPR) and the more recently developed electrochemical noise measurement technology. The suitability of these techniques to measure and monitor the corrosion of reinforcing steel in concrete is also discussed.

In this report, freezing and thawing test, carbonation test and length change test were carried out, determine the effects of differences in cement kind and curing methods on the durability of super-workable concrete, focusing mainly on placing during cold weather. Normal portland cement and three kinds of low heat type cement were used. A w/c of 50% was used for the normal portland cement, and a ratio of between 3O~35% for the low heat type cement. The curing methods of the specimens are standard curing, atmospheric curing, site sealed curing, site water curing and heat curing. During freezing and thawing test and accelerated carbonation tests, it was found that when heat curing is employed to prevent initial frost damage, if due consideration is not given to the temperature and wetness conditions of the curing concrete, there are cases where durability may be worsened instead of improved. With regard to the measurement of length change by the test methods adopted in current standards, there is a distinct possibility that the measurement values are not only due to drying shrinkage, but are also strongly influenced by autogeneous shrinkage of the concrete