Research in Progress (RIP)

SPR-4834: Riprap and Aggregate Polyurethane Stabilization for Drainage, Erosion Control and Road

Thu, 31 Aug 2023 16:34:53 GMT

This study presents a comprehensive investigation of polyurethane-bonded aggregate layers for drainage and erosion control applications in two phases. In Phase 1, laboratory tasks include identifying suitable aggregate sources, characterizing physical properties, optimizing mix proportions and mixing methods, and conducting comprehensive laboratory testing. Phase 2 focuses on site selection, construction, and in-situ performance monitoring. The study aims to optimize design parameters, assess environmental impact, and provide guidelines for successful implementation of polyurethanebonded aggregate technology.

Applications of Elastomeric Polymers for Accelerated Bridge Construction and Retrofit

Tue, 10 Mar 2020 15:15:15 GMT

Elastomeric polymers such as polyurea and polyurethane are nonlinear elastic materials with high tensile strength and strain capacity, adhesiveness, and resistance to permeability and environmental conditions. They have been used commercially as waterproofing and anti-blast coating for reinforced concrete components. While the elastomeric polymer is an interesting material with unique characteristics, there has been limited research on its potential structural applications. A number of research studies have shown the remarkable increase in flexural and shear strength of polyurea coated reinforced concrete beams. Further research is needed to explore the application of polyurea coating system as a new structural material in the bridge industry. This proposal takes the first step of a long-term research vision to examine and investigate the innovative applications of elastomeric polymers and specifically polyurea coating in accelerated bridge construction. The focus of this proposal is on the application of elastomeric polymer coatings for design and retrofit of side bridge girders. There are three aspects that can be considered for this application: (i) enhancing the flexural and shear strength of the beam through the application of a spray coating, (ii) enhancing the weather resistivity, which is especially important for side beams, and most importantly, (iii) overheight vehicle collision impact resistance. This proposal only focuses on the flexural and shear strength of polyurea coated RC beams. This simple step is taken to start gaining experience and knowledge on this relatively new material, and incrementally examine other aspects of the applications and other potential applications through future proposals and other funding opportunities. The research team plans for an experimental-analytical research effort, to develop simple phenomenological material models for the polyurea coating system and to investigate the potential cost vs. benefit of the coating in design and retrofit of side girders.

Nano-Engineered Polyurethane Resin - Modified Concrete

Fri, 01 Aug 2014 01:15:16 GMT

Latex modified concrete (LMC), also known as polymer portland cement concrete refers to hydraulic cement mixed with organic polymers that are either dispersed or redispersed in water. The dispersion of polymers in water is sometimes referred to as emulsions. When polymer emulsions are mixed with portland cement concrete, the polymer particles come together to form a polymer film coating on aggregate particles and cement grains, and seals any voids or microcracks. The resulting mixture of polymer emulsion and portland cement concrete will have higher strength, high resistance to chloride penetration and is more inert to chemical attack than plain cement. One of the weak links in a cement-aggregate composite material is the bond between the matrix and the aggregates. To improve the performance of the alternative cement binder (ACB), the research team will develop a Nano-Engineered Polyurethane Resin (NEPU) resin to act as an intermediary between the aggregates and the ACB matrix. The NEPU will be used to precoat the aggregates prior to their placement within the ACB matrix. Embedded within the NEPU will be grains of the ACB. Then, when combined with the ACB and water, the unhydrated ACB particles embedded within the NEPU-coated aggregates will react with the surrounding matrix during hydration, providing an enhanced interfacial zone and corresponding improvement in the material properties of the hardened material. In the proposed work, the used of bio-based NEPU emulsion for LMC application will also be investigated. The characterization of NEPU including cure kinetics, rheology, UV resistance, and flame resistance will be conducted. The proposed NEPU-modified concrete will be subjected to physical and mechanical testing. The optimal composition of NEPU system will be investigated for determining the percentage by weight of nano-clay and soy-content.

Soy-Based UV Resistant Polyurethane Pultruded Composites: Phase II

Thu, 03 Jan 2013 15:11:24 GMT

Development of affordable soy-based aromatic and aliphatic PU composites with improved mechanical and environmental performance is the focus of the proposed study. In our previous study, we have successfully manufactured both aromatic and aliphatic PU composites with 20% soy content. Neat resin samples of base PU and soy-PU were manufactured to evaluate the performance of the resin system. As the polyol and the isocyanate components of the PU resin system are susceptible to moisture, a novel mixing process was developed to make void free neat resin samples. A new metering unit system and an injection box were integrated with the pultrusion machine to manufacture PU composites. The mechanical performance of the neat resin samples and pultruded composites was evaluated. The performance of the soy-based resin is comparable to the base PU resin. However, aromatic PU based composites have poor environmental stability under UV light exposure and require specialized painting to provide protection. Aliphatic PU resins provide improved UV resistance but exhibit lower mechanical performance in comparison to aromatic polyurethanes. We have conducted preliminary studies on feasibility of incorporating nano-engineered fillers in the aliphatic PU resin system to compensate for the reduction in mechanical properties. In the proposed research, the current on-going work will be expanded to manufacture aromatic and aliphatic PU composites with increased soy content. Also, the initial study conducted for incorporating nano-engineered fillers in the aliphatic PU resin system will be used to manufacture PU nanocomposites. Fillers such as titanium dioxide will be mixed with the resin to obtain desired color for the finished part. The cure kinetics of the PU systems will be studied by differential scanning calorimetry (DSC) and the reaction rates of the aliphatic and aromatic polyurethanes will be compared. Mechanical and environmental performance will be evaluated by conducting tensile, flexure, impact, salt fog and UV exposure tests. The economics of aromatic and aliphatic systems will be assessed.

Acquisition of Equipments for Composite Manufacturing Laboratory

Thu, 03 Jan 2013 14:00:23 GMT

An interdisciplinary team of faculty has been formed to upgrade the Composite Manufacturing and Testing Facilities at Missouri S&T. The Metering Unit will be useful to manufacture composite pultruded parts using two part polyurethane resin system. The current pultrusion manufacturing facility is restricted to epoxy, polyester and vinyl ester resin systems. The Metering Unit will enable us to manufacture composite parts using polyurethane resin system. Composite test fixtures are required to conduct specialized tests like Compression after Impact, Open Hole Compression and Interlaminar Shear.

Soy-based UV Resistant Polyurethane Pultruded Composites

Thu, 03 Jan 2013 13:55:58 GMT

Polyurethane (PU) resin systems exhibit superior strength and damage tolerance relative to unsaturated polyester and vinylester pultrusion resins. Also, high pultrusion line speeds can be achieved using PU resins. A previous study, has successfully evaluated pultrudable PU with aromatic isocyanate and soy-based polyol (with 20% soy content). The performance of the soy-based resin is comparable to the base PU resin. However, aromatic PU based composites have poor environmental stability under UV light exposure and require specialized painting to provide protection. Aliphatic PU resins provide improved UV resistance but exhibit lower mechanical performance in comparison to aromatic polyurethanes. In the proposed work, we will investigate pultrudable PU resin systems with aromatic and aliphatic isocyanates, and soy-polyol. Neat resin coupons and pultruded composite parts will be manufactured using the developed aromatic and aliphatic PU resin systems. Also, parts will be manufactured by incorporating nano-engineered fillers in the aliphatic soy-based PU resin system to compensate the loss of mechanical performance over aromatic PU resins. The cure kinetics of polyurethanes will be studied by differential scanning calorimetry (DSC) and the reaction rates of the aliphatic and aromatic polyurethanes will be compared. Mechanical performance will be evaluated by conducting tensile, flexure and impact tests. The economics of aromatic system and aliphatic systems will be assessed.

Pultruded Composites Using Soy-Based Polyurethane

Thu, 03 Jan 2013 13:19:06 GMT

Fiber Reinforced Polymer (FRP) composites offer inherent advantages over traditional materials with regard to high strength-to-weight ratio, design flexibility, corrosion resistance, low maintenance, and extended service life. FRP materials can be used to replace traditional building materials like steel and wood. The application of composite materials will reduce cost and improve durability. One of the major cost drivers for composites is raw materials. Use of soybean-derived materials offers low cost raw materials. Development and performance evaluation of pultruded soy-based polyurethane composite panels is the focus of the proposed research. Soy-based polyurethane (PU) resin offers several benefits such as improved properties, faster production, and reduced VOC emissions. University of Missouri-Rolla (UMR) is collaborating with United Soybean Board (USB) to develop soy-based PU pultruded products for affordable housing and other commercial applications. Solid and core-filled pultruded parts will be manufactured at UMR and the performance of these products will be evaluated. Based on the test results, the resin chemistry will be modified to achieve improved structural performance and also to incorporate more soy content in the formulation without property degradation.