@MASTERSTHESIS{ 2020:1091859940,
 	title = {Diagnostic of concrete samples extracted from pile caps affected by internal swelling reactions.},
 	year = {2020},
 	url = "http://tede2.unicap.br:8080/handle/tede/1283",
 	abstract = "Due to the early deterioration of pile cap foundations in residential buildings and bridges in the
 Metropolitan Region of Recife, several studies have been conducted over the past decade to
 diagnose the problem and to discover the reasons for this process and to stabilize measures
 implemented that can provide an acceptable level of performance of such elements. In this master's
 research, samples taken from a pile cap block of a residential building built about ten years ago were
 studied. Laboratory tests were performed to evaluate the mechanical and transport properties of
 concrete samples, as well as their physical and chemical composition using advanced analyses. The
 tests performed were: compressive strength, static and dynamic modulus of concrete elasticity,
 apparent porosity, gas permeability, scanning electron microscopy, X-ray diffraction and raman
 spectroscopy. Visually it was possible to identify some evidences, such as: cracks in map in the
 foundation surface, white stains in the aggregates, silico-alkaline gel edges, cracks in the aggregate,
 leaching, stains around the aggregates, white material deposited in the voids and pores completely
 filled with ettringite crystals. The problem of the extensive cracking in the pile cap foundation had its
 origin in the delayed ettringite formation, possibly coming from a high heat of hydration coming from
 the concreting of the large volume of concrete. The mechanisms that caused damage to the
 investigated pile cap blocks were the internal expansion reactions, mainly the alkali-aggregate
 reaction and the delayed ettringite formation. The presence of crystalline products of the
 alkali-aggregate reaction was proven through physical-chemical analyses, such as Raman
 spectroscopy and EDS. As well as the ettringite crystals found in XRD standards, SEM images and
 the chemical composition of EDS. The values of the mechanical properties of concrete were
 influenced in different ways by the reactions, namely: the compressive strength of the concrete was
 not affected by the reactions. On the other hand, the values of the static and dynamic modulus of
 elasticity of the concrete tend to decrease, about 74% and 53%, respectively. The porosity showed a
 high value (between 9 and 10%), as well as the concrete permeability (​10​-16 and 10​-15​), determining
 the negative influence of ISR on the transport properties. Therefore, the methods used have proven
 to be effective in understanding the problem encountered and have the potential to be used in the
 design and execution of pile cap blocks.",
 	publisher = {Universidade Católica de Pernambuco},
 	scholl = {Mestrado em Engenharia Civil},
 	note = {Departamento de Pós-Graduação}
}