With the calculated chloride profiles, the time until initiation of reinforcement corrosion in the uncoated and coated concrete structures was assessed.
This analysis observed that, while the cross section analysis of some samples displayed visible lines of demarcation between individual layers coatsit was more common that the total fireproofing thickness appeared as a single layer.
Theses will be available within a few weeks after the actual thesis defence. Specification and planning The project specification for the building addition required that fireproofing materials be field applied to structural steel framing members i.
Since Evaluate concrete coatings thesis coats are required, the time frame for a complete application may span several days based on the recoat time between coats. Cracking and disbonding of the applied intumescent prompted a comprehensive coatings evaulation.
Other raised lifted areas were less apparent and were only identifiable by sounding tapping the steel with a metal wood chisel or hammer. The failure cracking, lifting on these panels was essentially similar to the problems that were observed in the field.
The water exposure consisted of placing the samples in a beaker containing water for four hours and then removing.
This surface film typically provides a line of demarcation between coats that is visible when a cross section of the film is viewed microscopically. There were also a few areas where cohesive disbonding within the fireproofing layer was observed.
The review showed that application of the fireproofing material was substantially complete prior to the installation of the exterior shell of the building. This was supported by the laboratory microscopic analysis of samples. The intumescent coating approved for the project was a one-component, solvent-based coating applied at up to 25 mils dry film thickness per coat.
Mechanisms of chloride transport in cementitious coating systems were studied, taking into consideration chloride diffusion and chloride binding.
Cracks in the dark blue topcoat often followed cracks in the underlying fireproofing. Review reveals exposed system Following the site visit, inspection reports from the coating application were obtained and reviewed. Further review of the application records lead to the conclusion that proper recoat intervals between coats of the fireproofing material likely were not observed.
Although it was obvious that much of the coating system would need to be removed and replaced, in this case, the coating manufacturer was asked to develop a written repair procedure for evaluation of the fireproofing system to determine whether intact areas could be salvaged and repaired.
The image above shows typical crack formation in the fireproofing material. Cementitious coatings can be used to protect low quality concrete structures against the ingress of aggressive substances, and to extend the service life of the reinforced concrete structures.
Once inserted, the entire fireproof system could be removed for several inches until adhesion eventually improved. The applicable test method is based on the depth of penetration of a specific type of indenter gauge that is forced into the coating film under specified conditions.
The plan indicated that the number of coats required on a given structural member ranged from two to 12, with total dry film thicknesses ranging from approximately 50 to mils. The thicker film sample, which already exhibited cracking before water exposure, exhibited additional cracking and the thinner sample had lifted from the panel surface.
Cause determined The results of the investigation concluded that weathering exposure of the fireproofing was the primary cause of the observed failure. The testing indicated that untopcoated fireproofing applied to structural steel in the building addition that was exposed to moisture would have reacted similarly.
System knowledge is key The problems observed underscore the importance of understanding the coating materials specified and applied for a project—particularly when the material plays an important role such as in fireproofing. The insufficiently cured coating layers may also remain soft as was observed in some areas of the building.The direct tension pull-off test has gained popularity as a test method used in the laboratory and especially in the field to assess the quality of bond between externally bonded fiber-reinforced polymer (FRP) repair materials and concrete owing to its low cost and simple procedure.
However, the. EVALUATING SHRINKAGE AND CRACKING BEHAVIOR OF CONCRETE USING RESTRAINED RING AND FREE SHRINKAGE TESTS By.
Adress Gerdagatan 13, 62 Lund Telefon 00 00 (vxl) Telefax 86 44 Internet killarney10mile.com Department of Technology and Society Life Cycle Assessment of Concrete Jeannette Sjunnesson Master thesis September Environmental and Energy Systems Studies.
This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital coatings using the identified coating characterization methods and tests. The final objective was to evaluate the experimental data and provide scientific reasoning for any.
Research Paper INNOVATIVE USE OF PAPER INDUSTRY WASTE (HYPO SLUDGE) IN DESIGN MIX CONCRETE These tests were carried out to evaluate the mechanical properties like concrete. All the inks, dyes, coatings, pigments, staples and "stickies" (tape, plastic films, etc.) are also washed.
Bond of Epoxy-CoatedReinforcement: Bar Parameters by Can Chul Choi, Hossain Hadje-Ghaffari,David Darwin, and Steven L.
McCabe Keywords: bond (concrete to reinforcement); coatings; deformed reinforce to help evaluate the effect of epoxy coating as a func.Download