O objetivo deste trabalho é analisar a resistência à compressão do concreto e seus possíveis efeitos com o reuso da água e dos resíduos de lavagens dos caminhões betoneiras. A revisão bibliográfica sobre o assunto proposto foi estudado e discutido em países como Grécia, Taiwan, Alemanha, Itália, Cingapura e outros, o que serviu de apoio e reforço para este trabalho. O método para analisar a resistência à compressão foi de comparação entre uma amostra controle (traço padrão de 30 MPa) e amostras com diferentes composições. O resultado de cada amostra foi diferente em função de sua composição, no entanto, pode-se afirmar ganho econômico na ordem de 20,21 R$/m3, além da resistência à compressão ser maior que 90% da amostra controle. As análises realizadas nas amostras através de DRX, MEV e EDS comprovaram que não houve síntese de novos minerais, somente pequenas quantidades (menor do que os limites de detecção do método de DRX) de alumino-silicatos e quartzo dissolvidos que foram sintetizados em novos minerais cristalinos, que podem ser atribuídos como substancias amorfas em estado sol-gel. Com o resultado observa-se que o reuso da água de lavagem dos caminhões betoneiras não interferem na resistência à compressão de novos concretos, assim como o resíduo de lavagem que não apresentou nenhum elemento diferente do composto no cimento, também não interfere na resistência à compressão de novos concretos, desde que haja controle da água presente. / The objective of this study is to analyze the strength of concrete compression and its possible effects on water reuse and waste washes of concrete mixer trucks. The literature review on the proposed subject was studied and discussed in countries like Greece, Taiwan, Germany, Italy, Singapore and others, which served as support and reinforcement for this work. The method for analyzing the compressive strength was compared between the control sample (standard stroke 30 MPa) and samples with different compositions. The result of each sample was different depending on their composition, however, it can be stated economic gain on the order of 20,21 R$/m3, in addition to the compressive strength is greater than 90% of the control sample. The samples were analyzed by DRX, MEV and EDS showed that there was no synthesis of new mineral, only small amounts (lower than the detection limits of the DRX method) dissolved alumino-silicates and quartz which have been synthesized into new mineral crystalline, which can be assigned as amorphous substances in sol-gel state. With this result it was observed that the reuse of the concrete mixer trucks washing water does not interfere with the compressive strength of new concrete, as well as the washing residue which presented no different element of the compound in cement, does not interfere with the compressive strength new concrete, provided that control of the water present.

The electrical and optical properties of boron doped hydrogenated amorphous silicon thin films (a-Si) were investigated to determine the effect of boron and hydrogen incorporation on carrier transport. The a-Si thin films were grown by plasma enhanced chemical vapor deposition (PECVD) at various boron concentrations, hydrogen dilutions, and at differing growth temperatures. The temperature dependent conductivity generally follows the hopping conduction model. Above a critical temperature, the dominant conduction mechanism is Mott variable range hopping conductivity (M-VRH), where p = ¼, and the carrier hopping depends on energy. However, at lower temperatures, the coulomb interaction between charge carriers becomes important and Efros-Shklosvkii variable hopping (ES-VRH) conduction, where p=1/2, must be included to describe the total conductivity. To correlate changes in electrical conductivity to changes in the local crystalline order, the transverse optical (TO) and transverse acoustic (TA) modes of the Raman spectra were studied to relate changes in short- and mid-range order to the effects of growth temperature, boron, and hydrogen incorporation. With an increase of hydrogen and/or growth temperature, both short and mid-range order improve, whereas the addition of boron results in the degradation of short range order. It is seen that there is a direct correlation between the electrical conductivity and changes in the short and mid-range order resulting from the passivation of defects by hydrogen and the creation of trap states by boron. This work was done under the ARO grant W911NF-10-1-0410, William W. Clark Program Manager. The samples were provided by L-3 Communications.