Concrete outdoor exposures

Under long-term outdoor exposure, involving frost action and car-bonation, latex-modified mortar shows increased resistance to weathering in comparison with conventional mortar and concrete. The weatherability of the latex-modified mortars is shown in Fig. 4.69The exposure test was done at the Building Research Institute Outdoor Exposure Site in Ibaraki Prefecture, Japan. Except for PVAC-modified mortars, the flexural and compressive strengths of most latex-modified mortars under outdoor exposure conditions tend to become nearly constant at one year or more, and a weatherability factor is greater or similar to that of unmodified mortar. 

Y. Ohama, T. Moriwaki and K. Shiroishida Weatherability of polymer-modified mortars through ten-year outdoor exposure, in Proceedings of the 4th International Congress on Polymers in Concrete, Institut fur Spanende Technologie und Werkzeugmaschinen, Technische Hochschule Darmstadt, Darmstadt, West Germany (1984), pp.67-71. 

Nischer, P. (1984) Influence of concrete quality and environment on carbonation, in Proc. of RILEM Sem. Durability of Concrete Structures under Normal Outdoor Exposure, 26—29 March, Hannover pp. 231—8. 

Under long-term outdoor exposure, involving frost action and car-bonation, latex-modified mortar shows increased resistance to weathering in comparison with conventional mortar and concrete. The weatherability of the latex-modified mortars is shown in Fig. The exposure test was... 

Concrete pipe—Used for surface drainage and for 15-in and larger pipes. Although it is available in smaller sizes, economics may limit its use. Fiberglass reinforced pipe—Used in corrosive service. It is limited to low-pressure and low-temperature systems. When fabricated, it is designed to meet very specific needs. For example, it may need to be able to withstand outdoor exposure or burying or may need to be sun retardant or made to project-specific dimensions. 

Wierig H. J. (1984) Longterm studies on the carbona-tion of concrete under normal outdoor exposure, 26.-29.3.1984, RILEM Seminar Hannover. 

A number of empirical calculations have been used to derive values of A and n based on such variables as exposure conditions (indoors and outdoors, sheltered, unsheltered), 28 day strength and water cement ratio. A wider range of empirically derived equations is given in Table 3.1. These cover different exposure conditions, curing and concrete properties. The easiest solution for a given structure is to take some measurements of carbonation depth, assume n = 1/2 and calculate A. This can be used to predict the rate of progression of the carbonation front. The time taken to reach the steel can then be estimated and the rate of depassivation calculated. 

Behavior includes aU the visible characteristics displayed by a chemical. PCB is a viscous to mobile, colorless to brown hquid that slowly spreads when spilled, depending on the ambient temperature and exact formulation. Indoor spills usually occur in small quantities on concrete, and the vapor will adsorb onto walls, carpeting, drapery, and metal objects. AU forms of exposure should be avoided and the airborne concentration carefiiUy monitored. On the other hand, outdoor spUls can range from a few drops from transformers to fuU trader tanks and can take place on either land or water. 

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