Eduvaldo Paulo Sichieri

Thermogravimetric analyses and mineralogical study of polymer modified mortar with silica fume

Mineral and organic additions are often used in mortars to improve their properties. Microstructural investigation concerning the effects of styrene acrylic polymer and silica fume on the mineralogical composition of high-early-strength portland cement pastes after 28 days of hydration are presented in this paper. Thermogravimetry and derivative thermogravimetry were used to study the interaction between polymers and cement, as well as the extent of pozzolanic reaction of the mortars with silica fume. Differential scanning calorimetry and X ray diffraction were used to investigate the cement hydration and the effect of the additions. The results showed that the addition of silica fume and polymer reduces the portlandite formation due to delaying of Portland cement hydration and pozzolanic reaction.

Identification of Urban Leprosy Clusters

Overpopulation of urban areas results from constant migrations that cause disordered urban growth, constituting clusters defined as sets of people or activities concentrated in relatively small physical spaces that often involve precarious conditions. Aim. Using residential grouping, the aim was to identify possible clusters of individuals in São José do Rio Preto, Sao Paulo, Brazil, who have or have had leprosy. Methods. A population-based, descriptive, ecological study using the MapInfo and CrimeStat techniques, geoprocessing, and space-time analysis evaluated the location of 425 people treated for leprosy between 1998 and 2010. Clusters were defined as concentrations of at least 8 people with leprosy; a distance of up to 300 meters between residences was adopted. Additionally, the year of starting treatment and the clinical forms of the disease were analyzed. Results. Ninety-eight (23.1%) of 425 geocoded cases were located within one of ten clusters identified in this study, and 129 cases (30.3%) were in the region of a second-order cluster, an area considered of high risk for the disease. Conclusion. This study identified ten clusters of leprosy cases in the city and identified an area of high risk for the appearance of new cases of the disease.

Study of the adherence between polymer-modified mortars and porcelain stoneware tiles

Despite the excellent characteristics of porcelain tiles, their application on building facades requires special attention, since this material differs from conventional ceramics and because facades are exposed to weathering that can damage ceramic revetments. The combination of polymer and silica fume to produce mortars results in excellent properties, which are ideal for repairs and revetments requiring high performance. Such improvements justify its study for the installation of porcelain tiles. This article presents bond strength results for mortars containing different amounts of polymer and silica indicating the applicability of these mortars as a construction material. To complement this study, the interface between the porcelain and the mortars was analyzed by scanning electron microscopy (SEM).

Electrochromic Properties of Sol-gel Coating of Nb2O5 and Nb2O5:Li+

Thin solid films of Nb2O5 and Nb2O5:Li+ were prepared by the sol-gel process using the sonocatalytic method. The films reported here were prepared from a NbCl5 as precursor and butanol as solvent. Through the addition of lithium salt LiCF3SO3 to the precursor solution, films with different electrochemical performance were obtained. The electrochemical and optical responses of the films were determined from the cyclic voltammetry and chronoamperometry measurements using a 0.1 M LiClO4/PC as electrolyte. The electrochromic properties of the films were investigated using in situ spectroelectrochemical method. They exhibit a gray coloration under Li+ insertion with a reversible variation of the transmittance in the visible and near infrared range between 20% and 80%.

Study for Utilization of Industrial Solid Waste, Generated by the Discharge of Casting Sand Agglomeration with Clay and of Blast Furnace Slag, in Concrete Composition

This research project accomplished a study on the technical feasibility of recycling industrial solid waste generated by the discharge of casting sand agglomeration with clay and blast furnace slag. For this, the plan proposed a methodology that initially establishes a process of solid waste encapsulation, by using solidification/stabilization technique on Portland cement matrices, in which the residuals act as small and large aggregates on the composition of concrete, and later it presents the possibility of using this concrete in the manufacture of concrete pieces (concrete blocks) for paving. The results obtained in this research achieved the objective set with great success, regarding the manufacturing of concrete pieces (blocks) for paving urban roads, whenever there is special vehicle traffic or demands capable of producing accentuated abrasion effects (surpassing the 50 MPa required by the regulation), which probes the technical practicability of using waste from sand casting agglomeration with clay and blast furnace slag used in this study, unlocking usage possibilities for construction.

A Modular System for Vertical Sealing Panels of Paper Tube

Problem statement: The society has been worried about the environment, especially due to the intense exploitation of natural resources, the large quantity of residues and their effects on the planet. In this context, the study and development of new materials in civil construction have become fundamental to make use of industrial residues or products discarded by the population. An alternative is to recycle paper and use it to manufacture cardboard tubes to serve as structural elements and sealing in the Architecture and civil construction areas, as Japanese architect Shigeru Ban has made in his projects worldwide for over twenty years. Approach: This paper addresses the elaboration of innovative modular panels made of cardboard tubes for vertical sealing and the construction system developed for their use. The panels underwent several analyses: compression resistance, sandbag impact and steel ball impact, and a test cell was also constructed to test their construction system and structural performance. Results: The panels showed good results in all tests, resisting a maximum of 5000 kgf compression load, besides high elasticity and tenacity in the impact resistance tests. Therefore, both the construction system and its complements have been patented. Conclusions: The panels showed enough resistance to be used in constructions. They offer several advantages to the sector of prefabricated buildings and housing, such as lightness, cleanliness and speed of execution and are a good alternative for some types of constructions, such as temporary, popular, emergency and movable. These panels are of large importance due to their recyclability, contributing towards environmental sustainability.