سال انتشار: ۱۳۹۰
محل انتشار: اولین همایش بین المللی بتن های ناتراوا مخازن ذخیره آب شرب
تعداد صفحات: ۱۰
M. Sadeghzadeh-Nazari – M.Sc. Student of Civil Engineering-Earthquake (Structural) Engineering, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, I.R. Iran
M. Pourlak – M.Sc. Student of Civil Engineering-Hydraulic Structures, Islamic Azad University South Tehran Branch, Tehran, I.R. Iran
Concrete has shown good performance as a general-purpose material for constructing non-permeable and non-osmotic structures such as fluid containers. Based on the mixture design and how it is placed, concrete can be almost impermeable. Guidelines for construction and mixture design are offered. Nevertheless, at regions of joints or discontinuities or while confronting severe situations such as longtime contact with strong acids other provisions should be considered in order to maintain the concrete impermeability. There are several means such as air-entraining, adding a synthetic fiber, a pozzolan like fly ash or silica fume, ground slag, and a superplasticizer to the concrete mixture that really help reduce the permeability of concrete. In this paper, some practical methods to make concrete structures non-osmotic or non-permeable such as taking advantage of waterstops as well as sealants are investigated. Besides, some curing methods which help maintain concrete in good position according to its osmosis condition are also discussed. The key factors affecting porosity are examined, as well as their relationship to moisture-related failures of seamless products. Destructive (DT) and non-destructive test (NDT) methods for liners and coatings are also discussedin the end. Describing the tests procedure, which provides factors that lead us to measuring concrete permeability, sampling conditions, test validity a nd finally the test report is revealed.It is readily apparent that the best way to eliminate moisture transmission problems is to prevent it by creating a concrete which has minimum shrinkage and capillary pores. This is done by carefully controlling the concrete mixture design with attention paid to minimizing total water, keeping the w/c ratio low, using PVC, expansive rubber, and metal waterstops as well field molded or performed sealants. Not only will this provide the least permeability, but it also provides the most durable concrete.