ABSTRACT The present work assessed the feasibility of applying blasted copper slag (BCS) as addition to cementitious composites. Series with 0-15% of BCS were produced and characterized by compression strength, durability, spread and specific gravity. In fresh state, the workability was enhanced in until 250% when adding the slag. Besides, both mechanical strength and durability indicators of BCSR-added concrete were also improved. Although the greater strength at the ages of 7 and 28 days was achieved for the reference concrete, concretes containing 5% and 7.5% of BCSR also reached the expected resistance of 30 MPa at 28 days. Concretes containing 5% and 10% of the slag were the ones that less absorbed water. The reduction in capillary absorption reached 63% in comparison to the ref concrete for 5% BCS-modified concrete. The incorporation of BCS improved the performance of the reference concrete in terms of both mechanical strength and durability. So, the reuse of the BCS produced after abrasive blasting in concretes was viable and sustainable disposal alternative.

RESUMO Fibras de aço são largamente utilizadas para os mais diversos fins na construção civil. A principal utilização é para reforço estrutural. Nessa aplicação as fibras atuam como ponte de transferência de tensão no compósito por meio do atrito entre a fibra e a matriz. Um meio para potencializar a aplicação de fibras em compósitos cimentícios é a alteração da superfície das fibras por meios físico químicos de modo proporcionar maior interação entre a fibra e a matriz. Neste trabalho é proposto um tratamento químico com dois tipos de silano, o Tetraetoxissilano (TEOS) e o Glicidoxipropiltrimetoxissilano (GPTMS). Foram realizados tratamentos de funcionalização por processo úmido e rota ácida com banhos sequenciais e cura após tratamento com silanos em porções de 1 e 10% em volume na solução e posteriormente analisados por MEV/EDS e método gravimétrico. Foram obtidas fibras de aço com silanos depositados em sua superfície. Foi verificado que quanto maior a concentração do banho de silano, maior é a deposição de silano na superfície das fibras. Em paralelo, verificou-se o aumento expressivo da concentração de silício em função do teor de silano nos banhos de funcionalização. Também se verificou que os filmes de silano quando espessos apresentam fragilidade à abrasão, sendo possível remover parte do filme por meio do atrito entre as fibras.

ABSTRACT Steel fibers are widely used for the most diverse purposes in civil construction. The main use is for structural reinforcement. In this application, the fibers act as a stress transfer bridge in the composite through the friction between the fiber and the matrix. One way to enhance the application of fibers in cementitious composites is to change the surface of the fibers by physical chemical means in order to provide greater interaction between the fiber and the matrix. In this work it is proposed a chemical treatment with two types of silane, Tetraethoxysilane (TEO)S and Glicidoxypropiltrimethoxysilane (GPTMS). Functionalization treatments were carried out by wet process and acid route with sequential baths and cured after treatment with silanes in portions of 1 and 10% by volume in the solution and later analyzed by SEM/EDS and gravimetric method. Steel fibers were obtained with silanes deposited on its surface. It was found that the higher the concentration of the silane bath, the greater the deposition of silane on the surface of the fibers. In parallel, there was an expressive increase in the concentration of silicon as a function of the silane content in the functionalization baths. It was also found that silane films when thick show fragility to abrasion, being possible to remove part of the film through friction between the fibers.

ABSTRACT The modulus of elasticity of concrete is often calculated as a function of the compressive strength, and as a deterministic value. However, variations in the aggregates properties may result in module values different than those estimated, which may lead to excessive deformation and eventual instability of the structure. In this work, the influence of the coarse aggregate batch variation on the variability of the modulus of elasticity of the concrete was investigated. Three different aggregate sources (one of granite origin and two of gneiss origin), three water/cement ratios (w/c) and five different batches of each aggregate were investigated. The compressive strength and static modulus of elasticity of the concretes were determined at 28 days. The analysis of variance (ANOVA) showed that the variable "batch" had a significant influence on the modulus of elasticity of the concrete, indicating that this property is a probabilistic variable indeed. The normality of the distribution of its values was attested, and values of characteristic modulus of elasticity were proposed, which were from 6 to 10% lower than the mean values. In addition, the use of gneissic aggregates led to modulus of elasticity values 30% higher than those of the concretes with granitic aggregates and equivalent compressive strengths, while the reduction of the w/c ratio from 0.71 to 0.46 increased the modulus of elasticity in about 5%.

ABSTRACT The study of silanes and polymers with special functions is increasing and the development of materials from silane-based polymers follows this trend. In this way, the hydrolysis of 3-Glycidoxypropyltrimethoxysilane (GPTMS) was studied as a function of the hydrolysis time in solutions with 50% of alcoholic solvents by infrared spectroscopy. It was verified that it was possible to analyze qualitatively and quantitatively the chemical reactions involving the hydrolysis / condensation of GPTMS and the main kinetics variations during the process. The results suggest that up to 30 minutes of hydrolysis, the predominant reactions are hydrolysis of the alkoxy groups, with the generation of the Si-OH groups and alcohol, in this case methanol. From 30 minutes, there is a large amount of silanols in the solution that tend to condense and form siloxane groups, which has this reaction accelerated from 60 minutes. Already, from 70-80 minutes, the reactions tend to decrease the kinetics, due to the absence of silanols and the hydrolysis / condensation process.

ABSTRACT This work aims the performance of concretes copper slag-added evaluated in fresh state by slump test and in hardened state by compression strength in 7 and 28 days of cement hydration, durability indexes as water absorption and binder efficiency by cement index. In fresh state, the results showed that the samples with copper slag presented lower slump than the reference sample. In hardened state, with 30% of copper slag addition, the compression strength was reduced only by 9% and 8% in comparison with the control series, for 7 and 28 days, receptively. Also, for 28 and 48 days of cement hydration, the water absorption showed lower values in the series with copper slag, indicating a beneficial performance of this waste in the cementitious matrix. Also, the binder efficiency was verified in the work. As the higher the slag in the mixture, lower was the cement consumption and, consequently, higher was the efficiency of the cement, resulting in a low increased in the cement index. The control series, at 28 days of cement hydration, achieved 11 kg•m-3•MPa-1 while the 30% copper slag-added series achieved 12 kg•m-3•MPa-1, which is only 9% higher than series with no consumption of copper slag, indicating a great performance of the copper slag in this cementitious matrix.

ABSTRACT This work deals with the effect in fresh and hardened properties of nano-TiO2 as addition in cement-based mortars. Three commercial nano-TiO2 powders were characterized by laser granulometry, XRD, FRX, zeta potential, BET and SEM. Two cementitious mortars were produced with nano-TiO2, an industrialized and a non-industrialized type; then, these mortars were characterized by flowability, surface roughness, flexural strength and surface fracture. The results showed that the nano-TiO2 addition reduced the flowability in terms of spread on table of the mortars. For surface roughness, in the industrialized mortars, the nanoparticles resulted in a smoother surface, while in the non-industrialized mortars, the nanoparticles formed a rougher surface. For flexural strength, in the non-industrialized mortars, the higher the nanoparticles amount, the higher the strength, while in the industrialized mortars no tendency was verified. In addition, from SEM analysis, it was noted that the fracture of the samples presented a tortuous aspect and growth through the region between cement paste and aggregates.

RESUMO Pavimento permeável é uma alternativa para o manejo das águas pluviais urbanas que permite a redução da precipitação efetiva através do processo de infiltração. O estudo avaliou a capacidade de infiltração de um pavimento permeável (PP) de blocos vazados de concreto no estacionamento da Universidade Federal de Pernambuco. A caracterização hidrodinâmica e a capacidade de infiltração foram analisadas em escala real, utilizando infiltrômetro de anel simples de 100 cm de diâmetro através do método Beerkan. Realizaram-se ensaios de infiltração em doze pontos do PP. Foi aplicado o algoritmo BEST na sua versão Best-Intercept e Best-Slope, para a estimativa dos parâmetros hidrodinâmicos da equação de van Genutchen e Brooks e Corey para as curvas de retenção e de condutividade hidráulica da superfície do pavimento permeável. Os valores da condutividade hidráulica saturada determinados pelo método BEST Intercept foram superiores aos obtidos pelo BEST Slope. Os valores da Sorvidade estimados pelo BEST Slope e Intercept foram semelhantes, sendo os valores do BEST Slope ligeiramente superiores. Observou-se moderada variabilidade da infiltração na superfície do PP, como também dentro do mesmo tipo de textura. O método Beerkan demonstrou ser adaptável para medir, em escala de campo, a infiltração tridimensional na camada de revestimento do pavimento permeável.

ABSTRACT Permeable pavement (PP) is an alternative for the management of urban rainwater that allows the reduction of effective precipitation through the infiltration process. In this study was evaluated the infiltration capacity of a PP of hollow concrete blocks in a parking lot of the Federal University of Pernambuco. The hydraulic characterization and the infiltration capacity were analyzed in real scale, using a simple ring infiltrometer of 100 cm in diameter through the Beerkan method. Infiltration tests were carried out at twelve points of the PP. The BEST algorithm was applied in it Best-Intercept and Best-Slope version, to estimate the hydraulic parameters of the van Genutchen and Brooks and Corey equations for the retention and hydraulic conductivity of the PP surface. The values of saturated hydraulic conductivity determined by the BEST Intercept method were higher than those obtained by BEST Slope. The sorptivity values estimated by BEST Slope and Intercept were similar, with BEST Slope values slightly higher. Moderate infiltration variability was observed on the PP surface, as well as within the same type of texture. The Beerkan method proved to be adaptable to measure, in field scale, the three-dimensional infiltration in the PP covering layer.

RESUMO O objetivo desse trabalho foi monitorar a hidrólise/condensação do tetraetoxissilano (TEOS) em função do tempo de diluição do silano, por meio da análise de espectroscopia de infravermelho (IR). Inicialmente foram avaliadas duas concentrações de silano (1 e 10% em volume). No entanto, verificou-se que em concentrações de 1% de TEOS não foi possível identificar as ligações químicas de interesse ao monitoramento da hidrólise de maneira adequada em regiões características do espectro de infravermelho. Definida a concentração adequada, o monitoramento da hidrólise/condensação foi realizado por meio dos espectros de infravermelho obtidos em soluções hidrolisadas à temperatura ambiente e extraídas a cada 10 minutos. Verificou-se que as reações de hidrólise dos grupos alcóxi aceleraram em 40 minutos a partir da diluição do TEOS. Em paralelo, a condensação dos silanóis também acelerou, devido ao aumento na sua concentração na solução. Após 70 minutos, a hidrólise/condensação apresentou uma desaceleração por meio da formação de siloxano e devido à hidrólise completa dos grupos alcóxi do TEOS. A hidrólise do TEOS em soluções com baixo teor alcoólico (em torno de 50% em volume) não mostrou prejuízos para o monitoramento das reações de interesse do sistema, apresentando cinética de reação similar ao reportado na bibliografia, mostrando-se como alternativa aos sistemas com consumo excessivo de solventes orgânicos.

ABSTRACT The objective of this work was to monitor the hydrolysis/condensation of tetraethoxysilane (TEOS) as a function of the silane dilution time, through infrared (IR) spectroscopy. Initially two concentrations of silane (1 and 10% by volume) were evaluated. However, it was found that at 1% of TEOS concentrations it was not possible to identify the chemical bonds of interest for the hydrolysis monitoring adequately in regions characteristic of the infrared spectrum. Once the appropriate concentration was defined, the hydrolysis/condensation monitoring was carried out using the infrared spectra obtained in solutions hydrolyzed at room temperature and extracted every 10 minutes. It was found that the hydrolysis reactions of the alkoxy groups accelerated in 40 minutes from the TEOS dilution. In parallel, the condensation of the silanols also accelerated, due to the increase in their concentration in the solution. After 70 minutes, the hydrolysis/condensation showed a deceleration through siloxane formation and due to the complete hydrolysis of the TEOS alkoxy groups. The hydrolysis of TEOS in solutions with low alcohol content (around 50% by volume) did not show any damage to the monitoring of the reactions of interest of the system, presenting reaction kinetics similar to those reported in the literature, showing up as an alternative to systems with excessive consumption of organic solvents.