Papers by Keyword: Mortar

Abstract: The life cycle analysis (LCA) is a methodology that allows us to contemplate the environmental impact of a material during the different stages of the life cycle. The impact categories were used to measure the repercussions caused to the planet due to the high demand generated by construction materials. This study addressed the stages of a life cycle analysis, according to the ISO 14044 [1] standard, with the aim of evaluating, quantifying and comparing the environmental impacts associated with the manufacture of mortar with similar mechanical behavior: A conventional mortar and a geopolymeric mortar, the latter developed from a geopolymerization process of waste from the Peruvian mining industry [2,3]. The scope of the work sought to evaluate the main environmental impacts of both mortars, focusing on a "cradle to door" life cycle analysis. The application of LCA allowed optimizing the manufacturing process, reducing adverse environmental impacts. The results showed that the environmental impacts of the geopolymeric mortar presented better performance in the medium impact categories: Environmental impact and water consumption. On the other hand, the conventional mortar presented better performance in the stratospheric ozone depletion impact category.

Abstract: The construction sector uses high quantities of raw materials and consequently the demolition sector generates huge amounts of waste. Envisioning the future of the construction sector, new Circular Economy Business Models should be implemented to contribute to the development of the sector. These Business Models will be based on innovative recycling techniques able to provide the technical requirements of the construction materials. This work aims to valorize ceramic and concrete wastes as aggregates for the mortar manufacturing. The chemical composition of these materials with high proportion of silica and very low quantities of sulfates makes them appropriate for their application. The wastes were previously crushed to the required particle size (6mm). The crushed ceramic waste presents an important fines proportion, which will increase the water consumption in the mortar mixes.

Abstract: This study explored the effects of formulation modifications of natural hydraulic lime (NHL) mortars exposed to hot temperature and high humidity conditions. The modified mortars were seeded by oyster shell powder, partially replacing the sand. The mortar samples underwent a curing period of 56 days with five observation days. The pH, carbonation depth, flexural strength, compressive strength, sorptivity, and morphology were studied. The results indicated that seeded mortars were more successful at setting and hardening high humidity settings. In addition, curing the mortars at higher temperatures hastened the hydration reaction significantly. The data indicate that seeded mortars can improve performance in several areas, notably carbonation rate (25%-45%), flexural strength (16%-60%), compressive strength (20%-55%), and sorptivity (18%-25%). The experimental protocol shows that the hardened mortar pore system is affected by the water-binder ratio, hydration level, relative humidity, and carbon dioxide concentration. The hydration of mortar greatly influences its strength. Using oyster shell powder as an aggregate substitute increased the performance of the mortars by microstructure and capillarity development. This circumstance is significant in our comprehension of modified lime mortars and seeding compounds, especially in hot-humid environments.

Abstract: Using alternative resources from industrial by-products to produce aggregates while keeping production costs as low as possible would be environmentally beneficial and profitable. This study aims to examine the effect of the pore on mortar properties with eggshell powder (ESP) as its fine aggregate alternative based on two fundamental properties: microstructural and mechanical strength. The study replaced the sands (by volume) with ESP in the usual mortar mix with 10%, 20%, 30%, 40% and 50% chicken eggshell powder. The mortars underwent a wet curing period of 56 days with five observation days. The standard mortar properties, such as pH, carbonation depth, compressive strength, and sorptivity, were investigated. The findings show that the replacement rate significantly impacts the water-cement ratio, carbonation rate, sorptivity and compression strength. The additional calcareous of ESP is believed to have improved the mechanical component of the connection. There are no significant differences in pH for the control (R₀) and modified mortars. The greatest replacement percentage of 20% is advantageous for carbonation rate acceleration, sorptivity and early compressive strength. However, if the specifier focuses on pH and sorptivity improvements, no formulation alteration is required.

Abstract: Over the decades, innovative techniques have been introduced and developed in the building heritage which make use of composite materials whose main objectives are bending and shear reinforcement, increasing ductility and limiting cracks. The use of composite materials with steel, carbon, glass and aramid fibers are already codified in the technical standards, now the challenge is the use of more sustainable materials. This paper focuses on a simple and effective bamboo fibers reinforcement of structural and non-structural commercial products such as mortar and plaster with different mechanical characteristics, trying to improve ductility without worsening their strength and mechanical stiffness. In particular, a plaster and a mortar with 2% (by weight) of bamboo fibers of Phyllostachys Iridescens species has been analyzed. A mechanical characterization is carried out evaluating flexural strength, compressive strength and fracture energy. The effectiveness of the reinforcement is shown through the comparison with the unreinforced materials.

Abstract: The sustainable building aims to minimize environmental impact by reducing carbon dioxide pollution by using by-products. Concrete materials are well-known for being the most extensively used construction material. Carbon dioxide emissions are the permissible greenhouse gas emissions that would have an impact on the long sustainability. Blast furnace slag reduces carbon dioxide emissions as an environmentally responsible building material, and sustainable steelmaking aims to minimize waste. Steel corrosion and chloride damage are several of the most apparent problems for concrete structure durability. Incorporating BFS into the cement is beneficial for concrete durability as the Structures' serviceability increased. This study aimed to explore the material properties and compressive strength of BFS mortar while considering the replacement ratio, Blaine fineness of the BFS, and curing conditions. This study mainly discovered that substituting BES for cement in the mortar increased the compressive strength and durability factor, indicating that the material's properties depend on the BFS, based on the experimental results, which cover the materials properties and salt preventive property. The low water-to-binder ratio (W/B) of the BFS-blended cement mixture is the reason for this. The study reported that the investigation of salt preventive by adding BFS with a low Blaine fineness and average substitution ratios (45%) could improve the compressive strength of BFS mortar samples. These mortar samples were even more resistant to carbonation, which could also be attributed to the hydration products of BFS.

Abstract: Geopolymer is an alternative cementitious material produced by rich aluminosilicate mineral materials (Si-Al) combine with an alkaline activator. The objectives of this study are to study the effect of adding hydrogen peroxide (H₂O₂) and sodium dodecyl sulphate (SDS) as foaming and stabilizing agents, respectively to the fly ash (FA)-based geopolymer mortar properties. The geopolymer mortars were synthesized with a mixture of FA, alkaline activator and SDS with different H₂O₂ content. The geopolymer mortars were analyzed using compressive strength test, porosity test and Scanning Electron Microscopy (SEM) analysis. Geopolymer mortar with 1 wt% H₂O₂ content and 0.5 wt% SDS has the lowest compressive strength (8.67 N) compare to the other geopolymer mortar composition. As H₂O₂ content increase with presence of SDS, the formation of the pores also increased hence resulting in the low compressive strength of geopolymer mortar.

Abstract: The aim of this study was to examine the influence of flax fibre protection with the linseed oil and a matrix modification with cement substitution with metakaolin (in 10wt% and 15wt%) on the mechanical properties of cement-based mortars under severe environmental conditions of freeze/thaw cycles. Cement-based mortars (with the dimension of 40x40x160 mm³) were reinforced by 10mm long discrete flax fibres (Linum usitatissimum) and exposed to 51 freeze/thaw cycles under laboratory condition. Their compressive and flexural strengths, as well as specific energy absorption capacity were measured after freeze/thaw cycles and compared to the results of mortars cured for same time in water. Under freeze/thaw cycles mortars reinforced with linseed oil-treated fibres showed the same range of degradation of the compressive and flexural strengths, however, a more pronounced degradation of energy absorption capacity compared to non-treated fibre reinforced mortars was observed. The matrix modification, by partial cement substitution with metakaolin showed optimistic results under freeze/thaw cycles. The compressive strength when cement was partially substituted with metakaolin (in both dosages) increased whereas the flexural strength was slightly lower in case of 10wt% substitution and markedly lower under higher (15wt%) cement substitution. The most relevant is that the decrease of the energy absorption capacity of the fibre reinforced mortar was completely prevented when cement was substituted with metakaolin. It is shown that the energy absorption of the non-treated fibre reinforced mortars increases by 27% when cement was substituted with metakaolin (both 10wt% and 15wt%).

Abstract: The present study evaluated the engineering properties and microstructure of an alternative binder composed of calcium carbide residue and silica fume. The cementitious mechanisms of this alternative binder based on the pozzolanic reaction in raw materials. The ratio of calcium carbide residue and silica fume was decided based on the chemical composition of raw materials and their chemical reaction. The calcium carbide residue-silica fume mortar was prepared and tested for its compressive strength at several curing periods, with results then compared to conventional mortar made with ordinary Portland cement. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to investigate the microstructure of hardened mortars. The test results suggest that the compressive strength of calcium carbide residue-silica fume mortar continuously developed throughout the curing period. The relative compressive strength of calcium carbide residue-silica fume mortar reached 72.78% of the ordinary Portland cement mortar strength at 28 days curing age.

Abstract: Carbonatation represents one of the potential degradation processes whose can negatively affect the service life of constructions based on the inorganic binders. The carbonatation depth of the constructions when exposed to various environments is significantly dependent on the existing conditions. The most crucial parameters are the partial pressure of carbon dioxide and humidity. There were selected four environments for the deposition of samples made of the alkali-activated blast furnace slag mortars (exterior, interior, water and CO₂ chamber) in this study. These types of environments guarantee the variation of desired parameters influencing the carbonatation rate. The progress of carbonatation was evaluated with a selected technique in time intervals of 28; 56 and 84 days of the sample's exposition to the selected environments. The characterization was done using the destructive techniques (compressive and flexural strength, phenolphthalein method) as well as the non-destructive one like the Impact-Echo or the Ultrasound time passage measurement. The combination of these techniques allows to determine and evaluate the progress of carbonation without the destructive testing of the samples which is necessary for the real applications of these materials.