This paper analyzes the performance of various types of paints available in the Brazilian market, including PVA, matte acrylic, silicate, and lime paints within the context of their applicability to the conservation of historic building facades. Considering distinct suppliers and application methods, this study highlights the importance of tailoring paint selection to the preservation requirements of historic edifices, taking into account local preservation norms and the material characteristics of the buildings’ original construction. The paints were evaluated based on water vapor permeability, washability, and adhesion. Furthermore, the paints’ color variation with exposure to accelerated artificial aging was assessed. For testing purposes, specimens produced from cellular concrete slabs were used as substrates, which were coated with the paints under study. Based on the results, it was observed that, regarding the diffusion of water vapor, the silicate and lime paints presented the highest permeability values, and the acrylic and PVA paints had the lowest. Concerning washability, the silicate and lime paints showed the greatest wear. The adhesion tests revealed that, except for lime paint, detachment often occurred at the substrate. As for the accelerated aging test, lime paint exhibited the most significant color variation, losing its pigmentation considerably over time. With the results of this research and considering the main preservation requirements of historic coatings, silicate-based paints may be considered the most suitable.

Dregs waste, a byproduct from green liquor clarification in the pulp industry, is increasingly generated as global cellulose production rises. This accumulation, along with its underutilization, presents environmental challenges and opportunities for reuse. The study focuses on the high alkali content in dregs, which can impact cement durability. The main objective is to analyze the effect of dregs on the alkali–silica reaction in mortars. Dregs were incorporated into mortar mixtures at 0%, 5%, 10%, and 15% proportions relative to cement mass, using six types of Brazilian cement and a blend with silica fume. The alkali–silica reactivity was assessed via the accelerated mortar prism test (ABNT NBR 15577-4:2018), with compressive strength tests and scanning electron microscopy evaluating structural integrity and microstructural changes. The results indicated that adding 5% dregs improved compressive strength in certain mortars, such as CP V-ARI RS, CP II-F, and CP IV. However, at 15% dregs, compressive strength significantly decreased, particularly in CP V with 10% silica fume. Cements with high pozzolanic content, such as CP IV and CP III, showed strong potential to inhibit ASR expansion. However, of the 28 mixtures analyzed, only four containing CP III had expansions within the limits set by standards. This study highlights the potential of incorporating dregs as a supplementary material in cement, promoting sustainability in the industry and reducing environmental impact.

Accelerated population growth, coupled with high consumption of natural resources, requires research focused on waste utilization. Solid waste from the pulp mill, originating from the Kraft process, is generated in large quantities and, despite its potential, still lacks an adequate destination. This paper investigates the mechanical properties and durability of coating mortars with the addition (7.5% and 15%) of the dregs and grits wastes, comparing them to a reference mix. The results indicate that the incorporation of dregs into the cementitious matrix offers advantages over both the reference and the grits waste. The use of dregs shows better mechanical performance and an alkali-silica reaction expansion equivalent to the reference for the 15% addition. However, the 7.5% addition of dregs results in the highest expansion among all the mortars studied. Both residues exhibit an expansion behavior inversely proportional to the addition rate of the wastes. With the addition of grits, all mortars show characteristics similar to the reference. Thus, the study identifies the potential for reusing both residues.

Durante o processo de produção da celulose, por meio do método tradicionalmente conhecido como kraft, nota-se a geração de resíduos em meio as suas etapas onde, dois destes serviram como base de estudo deste trabalho, sendo eles o dregs e o grits. O objetivo deste trabalho é avaliar o desempenho da resistência mecânica e absorção de água por capilaridade de argamassas com substituição de 20% e 30% de uma fração do volume do agregado miúdo utilizado nos traços para a sua produção pelo resíduo dregs e grits. A partir dos resultados, é possível identificar o potencial de aproveitamento, justificando o seu uso devido a sua funcionalidade e viés sustentável frente a grande extração de agregados naturais na obtenção dos materiais convencionalmente utilizados.

O resíduo dregs, da indústria de celulose, apresenta características físicas e químicas promissoras para aplicação em materiais cimentícios, destacando-se como alternativa sustentável. Este estudo explora o uso de dregs em misturas ternárias como substituto parcial do cimento, nas proporções de 0%, 5%, 10% e 15%. As misturas também incluem escória de alto forno e cimento CP V-ARI. Em todas as misturas tem-se a substituição de 25% do CP V-ARI por combinações de escória e dregs. Considerando o potencial do dregs como fíler, foi aplicado o método de empacotamento de Wong e Kwan (2008) e De Larrard (1999) para otimizar as proporções de mistura. Ensaios como mini-slump test, densidade de massa e resistência à compressão foram realizados. Os resultados evidenciam que o método de empacotamento melhora o desempenho mecânico das misturas, apesar de não apresentarem diferença significativa, são satisfatórios visto que é feita a substituição do cimento por até 15% do resíduo.

The use of industrial residues as supplementary materials in cementitious systems has been investigated as a strategy to reduce the environmental impact associated with cement production. In this context, this study evaluated the use of dregs waste from the pulp industry in ternary cementitious mixtures optimized using particle packing methods. The mixtures were designed using the wet packing method proposed by Wong and Kwan and the analytical model of De Larrard, with 25% partial replacement of cement by combinations of ground granulated blast furnace slag (GGBFS) and dregs at 5%, 10%, and 15%. The pastes were evaluated through fresh-state tests, compressive strength, thermogravimetric analysis (TG/DTG), and environmental indicators. The results indicated a reduction in workability with increasing dregs content, associated with the morphology of the residue particles. Nevertheless, the optimized particle packing helped maintain the mechanical performance of the mixtures. Thermogravimetric analysis indicated a reduction in portlandite content and an increase in carbonate fractions in the mixtures containing the residue. CO2 emissions decreased with increasing cement replacement levels. Therefore, the results indicate that the combined use of dregs and GGBFS may help reduce cement consumption while maintaining mechanical performance and promoting environmental benefits.