In recent years, high strength concrete (HSC) is becoming an attractive alternative to traditional normal strength concrete (NSC), and is used in a wide range of applications. With the increased use of HSC, concern has developed regarding the behavior of such concrete in fire. Until now, the fire performance of HSC is not fully understood and more research is needed. Full-scale fire testing is time consuming and expensive, and the real fire scenario is different from the standard fire. Performance-based assessment methods, including numerical analysis and simplified method, are being accepted in an increasing number of countries. In this dissertation, the fire testing results both of HSC and NSC are presented, performance-based numerical models are developed to study the fire performance of reinforced concrete (RC) members, and simplified calculation methods are proposed to estimate the load capacity of fire-damaged RC columns/beams. A detailed and comprehensive literature review is presented that provides background information on the high temperature behavior of concrete materials and RC members, as well as information on fire performance assessment procedures and objectives. The fire testing results of seven batches of HSC and NSC are presented and discussed. The test results indicated that the post-fire re-curing results in substantial strength and durability recovery, and its extent depends upon the types of concrete, temperature level, and re-curing age. The fire tests also showed that violent explosive reduced the risk of HSC explosive spalling. The surface crack widths were also reduced during the re-curing process, and in most cases, they were found within the maximum limits specified by the American Concrete Institute (ACI) building code. / Numerical models are developed herein to investigate the behavior in fire of RC columns and beams. The models have been validated against fire test data available in literature, and used to conduct parametric studies, which focused on the size effect on fire resistance of RC columns, and the effect of concrete cover thickness on fire endurance of RC beams. Simplified calculation methods have been developed to predict the load capacity of fire damaged RC columns/beams. This method is validated by five case studies, including thirty-five RC columns tested by other investigators. The predicted results are compared with the experimental results, and the good agreement indicates the adequacy of the simplified method for practical engineering applications. / by Lixian Liu. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Prevention of the corrosion of steel reinforcement embedded in concrete is a constant challenge in engineering. A study of concrete surface resistivity versus elevation of partially immersed reinforced concrete structures in a marine splash zone has been developed and correlations made between concrete quality and chloride diffusion, i.e., aggressive ion permeability. A conditioning procedure was developed in which the concrete moisture content is increased by direct contact with fresh water for several days. The electrical resistivity of concrete is known to be primarily a function of the degree of water saturation. Correlations between field obtained concrete surface resistivity values versus chloride diffusivity, and between normalized resistivity measured on cores obtained from the field versus chloride diffusivity has been established. The resistivity values were measured on structures with different concrete mixes and various ages. / by Andres M. Suarez-Solano. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Chloride ions present in the marine atmosphere contained in marine aerosols is investigated for a relationship with chloride that accumulated into concrete. Chloride profiles are conducted on several concrete mixes containing fly ash, silica fume, and slag, with water to cementitious ratios of 0.35, 0.41, and 0.47. The chloride accumulation in concrete samples exposed to the environment is investigated with relation to the chloride deposition from the marine atmosphere measured via the wet candle test. Results indicate a possible relationship for the total accumulated chloride in the concrete with the accumulated chloride deposition (wet candle). Over the exposure periods, concrete specimens with 50% slag addition and 0.47 w/cm had the lowest average rates of chloride accumulation for deposition under 100 g/m2day. Chloride accumulation was lower in concrete containing 20% fly ash and 8% silica fume with 0.35 w/cm for chloride deposition rates over 200 g/m2day. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

The improvement in the impermeability of concrete was studied using different methods. The main aim was to investigate impermeability improvement of concrete and to compare these methods. Two different methods were examined to investigate and compare impermeability and strength improvement of concrete by using two different sets of concrete specimens. These methods included the application of coating materials to concrete and the production of concrete using different constituent amounts and types. The first set of concrete specimens was prepared by applying two different coating materials (a coating material including both powder and liquid components / and a coating material including only a liquid component) on reference concrete specimens separately. The second set of concrete specimens was prepared using different proportions of concrete constituents such as cement, water, steel and plastic fibers, mineral and chemical concrete admixtures. Various tests were conducted on both sets of concrete specimens in order to compare the permeability of concrete specimens. However, some of these tests v were not applied on all of the specimens because of test and material specifications. The tests were used to evaluate compressive strength, water absorption, chloride ion penetration and depth of water penetration under pressure. These test methods were carried out on concrete cube specimens and concrete cores taken from those specimens according to the relevant standards. It was found that the permeability of the concrete specimens decreased significantly when the coating material which was composed of the combination of powder and liquid components was applied on concrete specimens. However, permeability did not decrease significantly for concrete specimens coated with the coating material composed of only a liquid component. Significant improvement in the impermeability of the concrete specimens was observed when the amount of cement was increased, the water-to-cement ratio was decreased, mineral admixtures (silica fume and fly ash) and plasticizers were used. This improvement was associated with densification of the concrete microstructure and reduction in capillary pores as a result of pozzolanic reaction and due to reduction in water-to-cement ratio. Coating materials were determined to be effective for concretes with high permeability prior to coating whereas their effect was less significant for lower-initial permeability concretes. Moreover, the effect of coating materials on permeability differed depending on their chemical compositions. The effect of using steel fibers and plastic fibers for the improvement of concrete impermeability was found to be insignificant.

Orientador: Gladis Camarini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-19T14:19:57Z (GMT). No. of bitstreams: 1 Pereira_ValdirMoraes_M.pdf: 1471160 bytes, checksum: 1317b5951c4368324373d0e6c2a488ba (MD5) Previous issue date: 2011 / Resumo: Os mecanismos de transporte no interior do concreto são os principais responsáveis pela sua deterioração. Desta maneira, a permeabilidade deste material tem vital importância e influência na sua durabilidade, ou seja, influenciando na principal característica que determina a vida útil para o qual foi projetado. É a permeabilidade que controla a taxa de ingresso e movimentação de agentes deletérios que podem comprometer física e quimicamente a estrutura interna deste material, que pode ocasionar na deterioração da sua macro e microestrutura. Por isso, diversas metodologias têm sido empregadas para mensurar e avaliar essa propriedade do concreto; no entanto, grandes disparidades têm sido encontradas. Assim, este trabalho visa avaliar permeabilidade ao ar de concretos produzidos com cimento Portland de alto-forno (CP III - 40). O traço empregado nas séries de concreto produzidas foi nas proporções de cimento: areia: brita de 1:2:3. Foram empregadas três relações água/cimento (0,42 - 0,46 e 0,50), e os concretos submetidos à dois tipos diferentes de cura (imersa e ambiente) e ensaiados aos 7 dias, 28 dias e 350 dias. A metodologia empregada para a determinação da permeabilidade ao ar do concreto foi a metodologia proposta por Thenoz. Para complementar os resultados de permeabilidade ao ar foram realizados também ensaios para determinação do índice de vazios e absorção de água por capilaridade. Os resultados indicaram que os concretos com maiores relações água/cimento têm maiores valores de índice de vazios e apresentaram os maiores valores de absorção de água por capilaridade e permeabilidade ao ar. A cura imersa demonstrou ser mais eficaz do que a cura ambiente, pois os concretos submetidos a este tipo de cura foram os que obtiveram os menores valores de índice de vazios, absorção de água por capilaridade e permeabilidade ao ar. A idade de hidratação também influenciou nos resultados, onde idades mais avançadas também demonstraram menores valores de índice de vazios, absorção de água por capilaridade e permeabilidade ao ar. A análise da metodologia proposta por Thenoz para a mensuração da permeabilidade ao ar do concreto indicou que, de acordo com o número Mach, não há descompressibilidade do ar durante o ensaio. De acordo com o número Reynolds do escoamento, é possível afirmar que o escoamento durante o ensaio de permeabilidade ao ar proposto pela metodologia Thenoz ocorre sob regime laminar. De acordo com os resultados obtidos na análise fluido-dinâmica do escoamento, a metodologia Thenoz, para a mensuração da permeabilidade ao ar do concreto, mostrou-se eficaz para a determinação dessa propriedade do concreto / Abstract: Transport mechanisms in cement-based composites are primarily responsible for their deterioration. Thus, the permeability of cement-based materials is vital in the durability of concrete, which is the main characteristic that determines the life for which they were designed. It is the permeability, which controls the rate of entry and movement of deleterious agents that can compromise physically and chemically the internal structure of these materials, causing a deterioration of its microstructure. Several methods have been employed to measure and assess the permeability of concrete, but major differences have been found. Thus, this work is to assess the air permeability of concrete produced with Portland cement, blast furnace (CP III - 40). The dash employee in the series of concrete was produced in the proportions of cement: sand: crushed of 1:2:3. Relations have been employed three water / cement (0.42 - 0.46 and 0.50), and the concrete submitted to two different types of healing (submerged and environment) and tested at 7 days, 28 days and 350 days. The methodology used to determine the permeability of concrete was to air the methodology proposed by Thenoz. To complement the results of the air permeability were also conducted tests to determine the rate of empty and absorption of water by capillary. The results indicated that the concrete relations with major water / cement have highest rate of empty and had the highest absorption of water by capillary permeability and the air. The cure immersed proved to be more effective than cure environment, because the concrete subjected to this type of cure were those who received the lowest values of voids content, absorption of water by capillary permeability and the air. The age of hydration also influenced the results, where elderly also showed lower values of voids content, absorption of water by capillary permeability and the air. The analysis of the methodology proposed by Thenoz for the measurement of the air permeability of the concrete indicated that, according to the Mach number, there is incompressibility air during the test. In accordance with the Reynolds number of outlets, it can be said that the disposal during the testing of the air permeability methodology proposed by the Thenoz occur under laminar regime. The assessment of Thenoz methodology to measure the air permeability of concrete shows that this is an effective concrete test, according to fluid-dynamics analyzes evaluate / Mestrado / Arquitetura e Construção / Mestre em Engenharia Civil

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2018-02-16T17:20:40Z No. of bitstreams: 1 LILIAN CORPAS BUCENE OLIVEIRA.pdf: 2456363 bytes, checksum: dfcf0b460775e677213c888d5bb3611d (MD5) / Made available in DSpace on 2018-02-16T17:20:40Z (GMT). No. of bitstreams: 1 LILIAN CORPAS BUCENE OLIVEIRA.pdf: 2456363 bytes, checksum: dfcf0b460775e677213c888d5bb3611d (MD5) Previous issue date: 2017-12-14 / Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo - FAPESP / The growth of urban centers has created new challenges for construction activities. It?s not only the environmental point of view, but also from logistical and economic reasons, two aspects that stand out, which are the management of rainwater and a destination of solid construction and demolition residues aggregate (RCD) . One of the alternatives to relieve the drainage system is the pervious concrete pavement (PCP), which allow infiltration of water into the base or soil, reducing floodings, water accumulations on roads and improving aquifers supply. The PCP employs in its composition, little or no fine aggregates, what providing a higher a volume of voids to the element, and consequently permeability. The addition of RCD in the pervious concrete?s composition is justified both by the increasing difficulty of disposal of these materials and by the reduction of the extraction of natural aggregates, favoring a reduction of the environmental impacts generated by the civil construction. Therefore, the production of pavement using pervious concrete made with recycled concrete aggregate (ARC) is one of the alternatives that has been researched to reduce the environmental impact of construction, protecting water resources and being able to avoid flood areas of flood with a lower consumption of natural goods. The effectiveness of water infiltration capability can be partially compromised due to the occurrence of clogging, which is influenced by the type and size of the infiltrated sediment into to the water and the precipitation intensity. This research studied two different types of PCP, produced with and without ARC, evaluating their behavior regarding mechanical, physical and hydraulic properties. A comparison was also made between different types of sediments to simulate the permeation of the pervious concrete. For this, laboratory studies were carried out and also equipment was developed to simulate a real situation of application of this type of concrete. It was observed the influence on the characteristics of PCP, with the use of ARC, as well as the permeability index after filling with various types of materials. The PCP using recycled aggregates obtained a satisfactory result, it was also verified that the test method to obtain the permeability index or the infiltration rate influenced in the analysis. It may also be noted that the adaptation of ?in situ? laboratory tests performed in the laboratory has not been shown to be adequate to the actual situation due to the influence of the floor base. / O crescimento dos centros urbanos tem produzido novos desafios ?s atividades da constru??o civil. N?o apenas do ponto de vista ambiental, mas tamb?m por quest?es log?sticas e econ?micas, dois aspectos v?m se destacando no ?mbito do setor nas grandes metr?poles, que s?o o manejo de ?guas de chuvas e a destina??o de res?duos s?lidos de constru??o e demoli??o (RCD). Uma das ferramentas que pode ser utilizada para aliviar o sistema de drenagem ? o emprego de pavimentos de concreto perme?vel (PCP), que permitem a infiltra??o de ?gua na base ou no solo, diminuindo os picos de cheia, ac?mulos de ?gua nas vias p?blicas, melhorando o abastecimento dos aqu?feros. O PCP ? uma mistura que emprega na sua composi??o pouco ou nenhum agregado mi?do, proporcionando maior ?ndice de vazios ao concreto, e consequentemente um elevado coeficiente de permeabilidade. A adi??o do RCD na composi??o do concreto perme?vel justifica-se tanto pela crescente dificuldade de descarte desses materiais quanto pela redu??o da extra??o de agregados naturais, propiciando uma redu??o dos impactos ambientais gerados pela constru??o civil. Portanto, a produ??o de pisos, usando o PCP elaborado com o agregado reciclado de concreto (ARC) proveniente do RCD, ? uma das alternativas que v?m sendo pesquisada para reduzir o impacto ambiental da constru??o, protegendo os recursos h?dricos e evitando ?reas de inunda??o com um menor consumo de bens naturais. A efic?cia da taxa de infiltra??o da ?gua de chuva no concreto perme?vel pode ser parcialmente comprometida devido ? ocorr?ncia da colmata??o, que ? influenciada pelo tipo e tamanho do sedimento infiltrado junto ? ?gua e a intensidade da precipita??o. Esta pesquisa estudou dois diferentes tipos de PCP, produzidos com e sem ARC, avaliando seu comportamento quanto ?s propriedades mec?nicas, f?sicas e hidr?ulicas. Tamb?m foi realizada uma compara??o entre diferentes tipos de sedimentos para simula??o da colmata??o do concreto perme?vel, para tal, foram realizados estudos em equipamentos desenvolvidos para simula??o do processo de colmata??o em um canteiro real. Observou-se a influ?ncia nas caracter?sticas do PCP, com o emprego do ARC, bem como a taxa de infiltra??o ap?s colmata??o com v?rios tipos de materiais. O emprego do ARC propiciou resultado satisfat?rio nas caracter?sticas do concreto perme?vel e verificou-se que os m?todos de ensaio para obten??o do coeficiente de permeabilidade ou da taxa de infiltra??o influenciam na an?lise do concreto perme?vel. Tamb?m pode-se notar que a adapta??o de ensaios para an?lise ?in loco? reproduzidos em laborat?rio n?o se mostrou adequada ? situa??o real devido a influ?ncia da base dos pavimentos.