Experimental and numerical evaluation of cured in place pipe lining system for high temperature applications in sewer pipes

Some of the older cities across North America and Europe had been using steam driven HVAC systems since beginning of the last century. Consolidated Edison (Con Ed.) of New York operates the New York City steam system, the largest commercial district heating system in the world, with more than 100 miles of transmission and distribution pipes serving Manhattan Island. Other steam district systems exist in San Francisco, Harrisburg, Minneapolis, Pittsburgh, San Diego, and Detroit, some dating back to 1903. In those cities the sewer pipes are used as venues for discharging the waste steam condensate from the HVAC system. The city of New York is considering the rehabilitation of the Time Square, including the near-by sewer pipes which pass beneath the subway station and/or along the concrete wall. Rehabilitation of these sewer pipes requires trenchless technique, installation of CIPP liners. Therefore, in the event of a malfunction of the aging steam system and failed steam trap, the sewer pipes lined with CIPP liners might be subjected to direct steam injection and the temperature may soar as high as 212°F. The presence of steam and the associated elevated temperature inside the lined pipe could result in an environment, incompatible with standard CIPP lining products. The main objective achieved within the first phase of the research was to experimentally determine the thermal effects on the aging of resin used in CIPP liner. Therefore, the resins expected to perform well under prolonged exposure to elevated temperature (up to 212°F) were identified first. Total 1890 specimens (ASTM D638 and ASTM D790) were prepared using epoxy, vinyl ester and polyester resin which were subjected to cyclic thermal loading (maximum 540 cycles intermittently changing between 90°F and 212°F). Next the specimens were tested to obtain the modulus of elasticity value and stress-strain curve; thus to indentify the best resin to serve at elevated cyclic temperature. Raman spectroscopy, a technique used for studying the chemical composition and chemical bonds of materials, was also used to provide more fundamental understanding of the degradation of the resin materials at the molecular level. It was found that vinyl ester and epoxy resin performs better at elevated temperature application than polyester resin, although polyester resin is used in more than 90 percent of the CIPP projects as it is economical. Another objective completed at the second phase was to evaluate the stresses generated due to the thermal strain on the full scale specimens. At this phase CIPP liners were impregnated using the best two resin types performed at elevated cyclic temperature in the phase one and full scale specimens were prepared by lining steel host pipe. The full scale specimens were kept inside custom built oven and cyclic thermal load was applied. Stresses generated on the specimen due to thermal loading were observed by analyzing strain gage data. It was found that stresses developed in the liners impregnated with vinyl ester resin were significantly lower in comparison to the liners impregnated with the epoxy resin. In the third phase, numerical simulation of the effect of high temperature on a CIPP liner was performed and parametric study was carried out to compare and validate the results obtained in the second phase

Exploring Rapid Solidifying Fly Ash Cementitious Materials for Making Structural Components

Exploring Rapid Solidifying Fly Ash Cementitious Materials for Making Structural Components Authors Ms. Tulie Chakma - United States - Louisiana Tech University Mr. Stephen Gordon - United States - Louisiana Tech University Dr. Shaurav Alam - United States - Louisiana Tech University Dr. John Matthews - United States - Louisiana Tech University Abstract This paper presents experimental data on two distinct approaches for rapid curing geopolymer cementitious (GPC) materials that utilize class F fly ash. GPC is a material created through the combination of an alkali activator solution and fly ash, a waste product produced during coal burning in power plants. Rapid curing was achieved using ohmic heating and frontal polymerization approach. Ohmic heating uses electric potential where it is applied across the surface of freshly mixed geopolymer poured into a form-work to produce heat, causing the material to harden and cure to form Ohmic Cured GPC (OCGPC). On the other hand, frontal polymerization is a self-propagating exothermic reaction where the heat is applied on a local spot to initiate the reaction and then the heat producing polymerization front propagates and rapidly cures geopolymer components to form frontally polymerized GPC (FPGPC). Samples of both OCGPC and FPGPC were tested using compression tests (ASTM C109 - cube and ASTM C39 - cylinder) and viewed using Scanning Electron Microscope (SEM) imaging technique. In addition to those, Fourier-transform Infrared (FTIR) spectroscopy was used to determine the organic composition of the FPGPC samples. The proposed study has the potential for rapid construction of structural components and significant construction time savings

Tensile strength and porosity of regolith-based cement with human hair

Sustainable structures are an important area of research, particularly for anticipated extended human presence on the Moon or Mars. Persistent human presence on the Moon will require building materials that are already present at the site to construct bases. The high cost associated with reinforcing metal (rebar) in mission payloads necessitates the exploration of alternative reinforcement methods for sustained lunar bases. Human hair is strong in tensile strength and will become available in any long-term mission. By using otherwise wasted hair instead of heavy metal, mission payloads and costs could be lowered. Concrete workability, compressive strength, and porosity were measured for a series of different cement compositions. These compositions consisted of combinations of Ordinary Portland Cement (OPC), lunar regolith, deionized (DI) water and human hair. Increased workability and porosity were found for increasing hair concentrations. Compressive strength slightly decreased with increased hair concentration

Insulating Paint

The motivation behind this research was to find a way of providing extra insulation through a very common medium used in every building. We set out to answer the question whether a type of paint could be mixed that had significant insulating properties to effect the overall insulation of a space. The results are to be determined through the testing of the insulating properties of 4 samples. Through this data collection, we will be able to see the trend of insulating properties compared to each sample and choose which sample offers the highest amount of insulation and be able to maximize its effectiveness. The significance of this research is that if a paint can be created that offers insulating properties, it could prove to be very cost effective in helping save money through heating and air conditioner costs and cut back on the use of regular insulation in walls and ceilings

Evaluation of Compression and Flexure Properties of Different Geopolymer Mixes

Recent studies of heat-cured fly-ash-based geopolymer concrete (GPC) have shown its suitability for the fabrication of new precast structural members and improved structural health of existing infrastructure components using spot repair. However, GPC curing requires continuous moderate heating (145°F) for 5 to 18 hours, and thus, an oven or a heat source is essential for curing. Curing large structures requires large amounts of energy, which can offset the environmental benefits of using GPC. The frontal polymerization (FP) technique has the potential to remove this heat source from the equation and can enhance the curing of ultra-high strength fly-ash-based inorganic GPC that is embedded with organic polymer composites. Initiation of the curing process requires a one-time short-period localized heating. However, conducting FP on geopolymer concrete materials requires full evaluation of mechanical properties of different geopolymer mixes. The present study will focus on the evaluation of compression and flexure properties of different geopolymer mixes with a goal to lay the foundation for achieving frontally polymerized geopolymer concrete (FPGPC) materials