Cold in-place recycling with expanded asphalt mix (CIREAM) has become an accepted road rehabilitation technique in Ontario and other parts of the world given its advantages over regular cold in-place recycling (CIR) and other methods. Although CIREAM offers early strength advantages and extended paving periods among other benefits, late season CIREAM can be burdened by distresses such as ravelling, potholing and other moisture-induced damage. Limited information on the behaviour and failure mechanisms of CIREAM has also hindered its utilization in spite of the numerous benefits. This research investigated effects of additives on foam properties of roofing asphalt flux (RAF) binder in order to evaluate the suitability of the binder for CIREAM. The study also investigated how mixture variables and test protocols affect performance properties that relate to early strength and moisture resistance of CIREAM versus CIR. Indirect tensile strength testing with moisture conditioning was used to assess the effects of asphalt cement type (80, 300 pen grades and polymer modified asphalt), conditioning time, and additives such as Portland cement, foam stabilizers, polymers and fibers. Uniaxial cyclic compression with partial confinement was used to assess effect of additives on deformation resistance of recycled mixes. Although a siloxane-based stabilizer significantly improved the stability of RAF foam, the binder may not be suitable for CIREAM due to its limited expansion. The optimum binder content was found to be around 2 percent, which is significantly higher than the minimum 1 percent currently used in Ontario. Both Portland cement and the siloxane additive exerted significant positive effects on strength behaviour and moisture resistance of the recycled mixes. In regular CIR mixes, 2 percent binder content gave desirable early strength and strain performance compared to 1 percent. Application of controlled amounts of additives (e.g. Portland cement, foam stabilizers) and case-by-case evaluation can improve the performance properties of CIREAM and address the associated problems. The entire research effort described in this thesis was designed to provide advice on potential improvements in the CIREAM process as it is currently carried out in Ontario, and also help in developing quality control standards in CIREAM and other cold mix processes. / Thesis (Master, Chemistry) -- Queen's University, 2014-04-16 08:42:24.313

Master of Science / Department of Civil Engineering / Mustaque A. Hossain / Based on a 2017 report on infrastructure by the American Society of Civil Engineers, 13% of Kansas public roads are in poor condition. Furthermore, reconstruction of a two-lane concrete pavement costs between $0.8 and $1.15 million dollars per lane mile. High early strength Portland cement concrete pavement (PCCP) patches are widely used in pavement preservation in Kansas due to the ability to open to traffic early. However, these repairs done by the Kansas Department of Transportation (KDOT) deteriorate faster than expected, though, prompting a need for inexpensive, durable high early strength concrete repair mixtures that meet KDOT standards (i.e., a 20-year service life). This study developed an experimental matrix consisting of six PCCP patching mixture designs with varying cement content and calcium chloride dosage. The mixtures were subjected to isothermal calorimetry, strength testing, drying shrinkage, and various durability tests. The effects of cement content and calcium chloride dosage on concrete strength and durability were then investigated. In addition, the compressive strength development with time, the split tensile versus compressive strength relationship, and the shrinkage strain of the PCCP patching mixtures were compared to established relationships provided by the American Concrete Institute (ACI). Results showed a maximum 3% increase in total heat generated by various concrete paste samples in isothermal calorimetry testing. The minimum compressive strength of 1,800 psi required by KDOT could likely be obtained using any of the PCCP mixtures, regardless of the cement content or calcium chloride dosage used in the study. Furthermore, surface resistivity tests for mixtures containing calcium chloride could result in erroneous measurements. Only one mixture satisfied the maximum expansion and minimum relative dynamic modulus of elasticity required by KDOT. Some ACI relationships for shrinkage and strength development do not appear to be valid for high early strength PCCP patching mixtures.

Accelerated bridge construction (ABC) has become a popular alternative to using traditional construction techniques in new bridge construction and existing bridge deck replacement because of the reduction of time spent in field activities. A key feature of bridges built using ABC techniques is the extensive use of prefabricated components. Prefabricated components are joined in the field using small volume closure pours involving high performance materials (steel and concrete) to ensure adequate transfer of forces between components. To date, the materials developed for closure pours have been based on proprietary components, so a need has arisen for development of mixes that use generic components. The goal of this research was to create a method to develop concrete mixtures that are designed using generic constituents and that satisfy performance requirements of accelerated bridge construction closure pours in New England, primarily high early strength and long-term durability. Two concrete mixtures were developed with a primary goal of reaching high-early strength while maintaining constructability. The secondary goal of the concrete mixtures was to be durable; therefore, measures were taken during the development of the concrete mixture to generate a mixture that also had durable properties.

Se viene buscando optimizar la elaboración del concreto lanzado, pero en el proceso se deja de lado el control de calidad por lo cual es indispensable comparar la influencia de un componente primario como el cemento tipo IP y HE. La presente tesis tiene por objetivo realizar el estudio comparativo de concreto lanzado con cemento portland puzolanico tipo IP vs tipo HE en el revestimiento del túnel de la mina Orcopampa–Arequipa. Nos ha impulsado a investigar la necesidad de obtener la relevancia en el desempeño y las implicancias del cemento para shotcrete desde una visión técnica, a través de ensayos de campo y laboratorio. Considerando el enfoque técnico al determinar las diferencias entre el concreto lanzado con cemento Tipo IP y Tipo HE desde el análisis de resistencia a tenacidad y resistencia a la compresión. Realizando un tipo de Investigación básica, cuantitativa, descriptivo, aplicada, de campo con un diseño experimental, según el estudio es cuasi experimental, prospectivo por la cronología de observación, transversal según el número de mediciones, descriptiva, comparativa y explicativa. Los resultados estadísticos nos demuestran que si existen diferencias significativas de 62 % entre los resultados de la resistencia a la compresión del concreto lanzado cemento Tipo HE sobre el concreto lanzado con cemento Tipo IP en su totalidad de edades ensayadas. En el análisis estadístico de los ensayos de tenacidad se observa que el cemento Tipo HE tiene una mejor capacidad para absorber energía ya que tiene la característica de desarrollar resistencias a edades tempranas. It has sought to optimize the development of the shotcrete, but in the process neglects quality control so it is essential to compare the influence of a primary component such as cement type IP and HE. This thesis aims to conduct a comparative study of shotcrete with IP pozzolanic Portland cement type HE vs kind in the lining of the tunnel Arequipa Orcopampa mine. It has prompted us to investigate the need for relevance in the performance and the implications of cement shotcrete from a technical view, through field and laboratory tests. Whereas the technical approach to determine the differences between the shotcrete cement type HE type IP and from the analysis of toughness and resistance to compression. He made a type of Basic, quantitative, descriptive research, applied field with an experimental design, the study is quasi-experimental, prospective timeline for observation cross as the number of measurements, descriptive, comparative and explanatory. The statistical results show that if there are significant differences between the results 62% of the compressive strength of cement Type HE shotcrete shotcrete on cement type IP fully tested age. In the statistical analysis of toughness tests it shows that the cement type HE has a better ability to absorb energy and which has the characteristic of developing resistance at early ages.