The use ofCement-based composites natural fibers in cementitious compositesComposites still presents a limitation to their durability in the alkalineAlkaline matrix. Some treatments on the fiber are carried out in order to reduce its degradation in the matrix, such as surface treatment with NaOH. The objective of this study is to evaluate the durability of guaruman fiberGuaruman fiber (Ischinosiphon koern) with surface treatment with NaOH as a possible reinforcement for coating mortarsCoating mortar. For this, compositesComposites were manufactured with and without treatment in proportions of 0

The Amazon region faces a major obstacle caused by the high production of several natural fibersNatural Fiber, such as açaíAçaí (Euterpe oleracea). There is still no specific and consolidated destination for agro-industrial wasteWastes generated in the different stages of processing Amazonian fibers, causing environmental changes in the region. Furthermore, it is known that the use of these fibers can promote an increase in ductile behavior and tensile strength in cementitious composites. With the objective of contributing to the creation of new strategies that guarantee the improvement of mortarMortars properties and, at the same time, collaborate for an efficient disposal of the wasteWastes in question, this work aimed to evaluate properties of mortarsMortars in the fresh state with the addition of acai fibers. Three types of mortarMortars were developed: (1) reference (without the use of fibers); (2) with the addition of fibers without surface treatment; and (3) with the addition of material with surface treatment based on tannic acid with a concentration of 5

The characterizationCharacterization of ornamental rocksOrnamental rocks has the purpose of predicting the behavior of the rocks when exposed to various requests present in their place of application, seeking to know the feasibility of using the material. The objective of this work is to analyze the staining of the rocks after variations in exposure times. Four types of rocks were selected for the test: Dallas White, São Gabriel Black, Castelo Grey, and Siena White. The staining agents chosen were: lemon, oil, coffee, steel sponge and detergent, bleach, and degreaser. As a result, it was noticed that the stainsStain caused were more evident and accentuated as the time of exposure of the rocks to the staining agents increased, developing more accentuated and permanent stainsStain.

The use of natural fibers as reinforcement in cementitious composites has been explored as an alternative to the development of new materials for civil construction. Research that explores macro and microstructural parameters in a combined way in composites reinforced with natural fibers are still poorly explored. In this work, the compatibility effect of Malva (Urena lobata L.) on fiber-reinforced cement composites was evaluated dosages (0, 2 and 5%) with untreated and treated fibers (30 min in 5% of NaOH solution) were mixture with Portland cement and lime to application as coating mortars. Reaction rate by isothermal conduction calorimetry and 28 days reaction products of pastes were characterized with XRD, SEM, and MIP, as well as technological properties of mortars, such as mechanical strength, water absorption, and consistency were investigated in all dosages. The findings showed an increase in the cross-compatibility index of treated fibers (around 5%), resulting in a denser microstructure with reduced portlandite and calcite formation when compared with untreated Malva, due to the removal of sugar and impurities obtained with the NaOH treatment. MIP results exhibited a reduction on total porosity from ∼12% to ∼6%. Mechanical strength was lower in the untreated fibers (∼35% less than reference) with no significant difference with higher content, nonetheless, fiber treatment presented similar results to the reference. Water absorption were 8% lower to treated fibers. The incorporation of 2% by weight of treated Malva fibers in cement-based mortars presented better efficiency, offering a promising new material for cladding walls in building materials.

Guaruman fiberGuaruman fiber is a natural lignocellulosic fiber (NFL) extracted from the stalk of an Amazon plant (Ishinosiphon Koern) in the northern region of Brazil. The present work investigates the addition of 2.5, 5.0 and 7.5 wt.

The polishingPolishing process is an important phase in the processing of ornamental stones, through which it is possible to obtain materials with a high aesthetic standard desired by the international market. This process requires good equipment and a constant flow of water, in order to provide higher quality products. A well-polished material has a higher level of shineShine and is valued more. Thus, the present work aimed to propose a reduction in the water flowWater flow during the polishingPolishing process to evaluate the feasibility of reducing water consumption while increasing the quality of the final product. To carry out the study, three types of rocks were chosen: Corumba Grey, Dallas White and Itabira Ochre. The experiments proved to be efficient and the quantitative analysis can be an important tool in obtaining a brighter final product and, also, an opportunity to save water.

The natural fiber from açaí (Euterpe oleracea Mart.) is an example of agro-industrial waste generated in large quantities in Brazil. The objective of this work is to evaluate the technological characteristics of mortars in their fresh state, reinforced with the addition of natural açaí fiber, submitted to a type of surface treatment, such as immersion in NaOH, KOH and Ca(OH)2 in the concentration of 10%. The mixtures have a ratio of 1:3 (cement: sand) with additions of 0 (reference), 1.5, 3.0, and 4.5% of the açaí fiber, in relation to the cement mass. Tests were carried out to determine the consistency index, mass density in the fresh state, incorporated air content, and water retention. The results showed that the 4.5% mixture treated with KOH was the one that showed the best results due to its lower density and one of the highest water retentions.

Ornamental rocks applied to civil construction are subject to the appearance of cracks and ruptures. Some processes provide the rock with greater resistance to bending efforts: The resin coating method consists of applying a mixture of resin and catalyst on the surface to be used, while meshing is the process of fixing a fiberglass mesh on the unfinished face of the rock. This work shows the results achieved in hard body impact resistance tests, aiming to define and scale the increase in resistance using resin and screen in materials with a thickness of 0.03 m. The rocks used in this work are commercially known as Vicenza, Romanix, and Nevasca. The research results indicate the effectiveness of the application of resin and mesh provided by the significant increase in strength. However, the raw materials also achieved satisfactory results, especially the Nevasca material, which obtained the highest average of rupture heights.

Açai fiber has a characteristic that enhances its application as a reinforcement material in mortars. One of the major problems in the use of natural fibers in cementitious composites is the alkalinity of the porous of these materials, which can be solved by applying surface treatment to the fibers. The objective of this work was to evaluate four different forms of surface treatment of natural Açai fibers, washing them with water, with cyclohexane/ethanol, immersing them in a solution of NaOH or alkaline peroxide, adding them in 4% in relation to the mass of cement in mortars of cement, and lime for coating. Properties such as consistency, incorporated air content, linear shrinkage, mechanical resistance, and water absorption were evaluated, according to Brazilian standards. The results showed that the treatment with alkaline NaOH solution is the one that best managed to modify the surface of the fibers, improving the evaluated technological properties.

The structural masonry has as basic characteristic the use of the supporting walls, formed with structural blocks joined by seating mortar. The blocks must have compressive strength compatible with the loads to which they will be subjected to, and the mortar must be adequately resisted in order not to compromise the structure of which it is part of, and absorb the deformations to which the masonry is subjected. Two types of mortar bedding are recommended: full bedding, covering net area for unit, and face shell bedding, where the mortar is placed only in the face shell area of the block. This work aims to test the compression of face shell bedding concrete blocks prisms with two traces of mixed mortar with different compressive strength. It has been concluded that the increase of the compressive strength of the mortarinfluences the increase in the compressive strength of the prisms with face shell bedding type.

The main pathogens that occur in alkali-activated materials based on blast furnace slag are efflorescence and the black heart, due to the saturation of very high amounts of sodium. Therefore, the objective of this work was to measure the alkali mortars activated by a solution of 2.5, 5, 7.5, 10, 12.5, and 15M using sodium hydroxide, testing the material under compression and water absorption with 7 days of curing at room temperature, and thermal curing at 60 °C. The results show that the use of 12.5M and 15M causes the appearance of this pathology when curing in a normal environment, while compositions with 10M, 7.5M, and 5M present excellent technological parameters.

In the structural masonry system, the wall performs a structural function, absorbing the loads imposed on the system, being formed by blocks joined by seating mortar. In this constructive method, the quality control of the inputs and the correct dimensioning of the components is of paramount importance. In addition to the inputs, other factors can compromise the strength of the wall, for example the mortar bedding types. Two types are recommended, full bedding and face shell bedding. In full bedding, the mortar is disposed in all septum of the block. Therefore, this work has the objective of evaluating concrete blocks prisms with two mixed mortars ratios of different compressive strength. It is concluded that the increase of the compressive strength of the mortar influences the increase in the compressive strength of the prisms with full bedding type.

The dosage of activated alkali materials, as is the case with blast furnace slag mortars, is one of the great complexities of materials science. In this context, the objective of this work is to propose the mortar dosage 1: 1: 0.5 (precursor: aggregate: activator), varying the silica module of the solution by 0.3, 0.6, 0.9, 1.2, and 1.5, and performing compression, density, water absorption, and porosity tests, performing thermal curing at 60 °C and normal curing, with curing of 7 days. The results showed that the variation of the silica module significantly changes the results of the evaluated properties, with the best parameters obtained for a 1.2 module of silica.

The incorporation of waste from industries in construction is becoming an increasingly common practice; since in addition to decrease the amount of material disposed on the environment, it can further improve its properties. Among the residues in need of disposal is the waste from the paper industry. The objective of this work is to evaluate the incorporation of paper waste in ceramic tile. Thus, 0, 10, 20, and 30% incorporations were used to compare the results. The materials used in the research, clay and residue, were characterized by the grain size tests, chemical analysis, and actual grain density. To evaluate the best content of incorporation were made specimens of test and realized the tests of resistance to flexion, firing linear shrinkage and water absorption. The results indicated that it is feasible to use the incorporation of 10% residue, only because of economic and environmental issues, since the properties are altered in this incorporation.

The soil-cement blocks are an innovative technology that aims at the construction of masonry without the need of coating, adopting the modality of block modules. In addition, they are more sustainable for the fact that they are not burned, where the energy is smaller and less release of gases into the atmosphere. The objective of this work is the ratio of soil types (called A, B and C), extracted from the different fields of the municipality of Campos dos Goytacazes (by simplex methodology), in order to optimize the mixture and obtain the best technological conditions as compression strength and water absorption in blocks of soil-cement. As a result of this work, it was observed that, through the characterization, the soils show potential for the production of soil-cement blocks, besides determining the proportion of 32% of soil A, 37% of soil B and 31% of soil C being optimization of the evaluated properties.