Papers by Keyword: Cement Mortar

Abstract: With a growing global focus on sustainability, the construction industry is steadily replacing conventional materials with environmentally friendly alternatives. Plant-based fibers, particularly cellulose fibers, are increasingly considered as reinforcement in cement-based materials due to their favorable mechanical properties and renewable origin. Cement-based materials, despite their strength, are prone to porosity and moisture absorption, which compromise long-term durability. To address these challenges while promoting sustainable material use, this study investigates the effects of micro and nanoscale cellulose fibers extracted from sugarcane bagasse on the performance of cement-based materials. Cellulose fibers were obtained through a chemo-mechanical process and surface-modified to achieve hydrophilic and hydrophobic properties. The produced fibers were characterized using SEM and XRD, confirming predominantly amorphous structures and smooth, rod-like morphologies Mortar samples with hydrophobic cellulose microfibers (0.5% and 1%) and cement paste samples with hydrophilic cellulose nanofibers (0.1, 0.25, 0.5 and 1%) were prepared and tested for fresh and hardened properties. Results demonstrated that hydrophobic cellulose microfibers improved mortar workability by up to 13.6% and reduced water absorption by 31.5%, while also enhancing compressive strength (4.7% increase) and density (3.8% increase) at 0.5% dosage. However, higher fiber content (1%) led to entrapped air voids, reducing strength and density. In cement paste, hydrophilic cellulose nanofibers exhibited dual behavior: small dosages had negligible effect, 0.5% significantly improved density (4.9% increase) and compressive strength (38–40 MPa at 7–14 days), while higher dosages caused strength reduction and increased absorption due to fiber agglomeration. Overall, 0.5% fiber incorporation at both scales provided the optimal balance of strength, durability, and workability.

Abstract: This paper presents effect of low contents graphene oxide (GO) on the properties of cement mortar that could be developed for nano modification in cement composites. The characteristic of GO-cement mortars were first evaluated using slump flow test. Then, mechanical properties of GO-cement mortars were carried out. Specimens were made on a 5×5×5 cm³ cube mold with five different contents of GO (e.g., 0.01% to 0.05 %) using a water to cement (w/c) ratio of 0.485. The compressive strength tests were performed at specimen age of 3, 7, and 28 days. Results showed that the incorporation of GO significantly improved mechanical properties of GO-cement mortars. Further, the obtained compressive strength of mortars significantly increased and achieved the highest 28 day-strength by 63.6% at 0.04% GO.

Abstract: Water shortage is a major global issue affecting the construction industry. One possible solution is to use seawater instead of tap water in cement-based materials. However, this raises concerns about the impact on material properties. In addition, it is known that the use of volcanic pumice powder in cement mortar can improve its properties, but the combined effects of seawater and volcanic pumice powder have not been thoroughly investigated. This study aims to fill this gap by investigating the synergistic effects of seawater and volcanic pumice powder on the slump flow, compressive and flexural strengths, water absorption, and fracture toughness of cement mortar. The main variables in this study are the type of water (Mediterranean water and tap water) and the percentage of volcanic pumice powder (VPP). The volcanic pumice powder content is 0%, 10%, 20%, and 30%, replacing cement by mass. Based on investigation results, it was shown that the combination of seawater and volcanic pumice powder leads to less fluid and more viscous mortars compared to those made with tap water (TW). However, in the hardened state, seawater promoted the early precipitation of cement hydration, resulting in an increase in compressive strength from the second day until 28-days, along with an improvement in the transport properties of mortar at 28 days. Meanwhile, a noticeable decline in both strength and fracture toughness was recorded for ages more than 28 days and up to 90 days, compared to mortars cast and cured with tap water.

Abstract: The purpose of this study is to investigate the influence of the cement/sand (c/s) ratio on the behavior of cement mortar. The used c/s ratios in this study were 1:0, 1:0.45, and 1:0.83. The findings of this study showed that increasing the sand content reduces the compressive strength of the mortar mixture by 41.5 and 28.2% for the c/s ratios of 1:0.45, and 1:0.83, compared to the plain cement mortar (c/s: 1:0). The increase in sand content requires more water content to increase the workability and strength of the mixtures. However, the flexural strength slightly increased compared to the control mortar. In addition, to enhance sustainability, the cement was replaced with two waste industrial materials namely, micro silica (MS) and fume treatment plant (FTP) dust by 20% of cement weight. The modified mixtures (c/s: 1:0) also showed reduced strength at the testing age. The compressive strength of the modified mixtures was reduced by 50% and 19% for the FTP and MS-modified mixtures, respectively. On the other hand, the flexural strength was reduced by 19.1 and 30.2% for the FTP and MS-modified mixtures. This reduction can help achieve certain strength requirements by lowering the cement content in cement concrete mixtures.

Abstract: In this study, the blast furnace slag (BFS) was used to replace 30% cement (weight replacement), freshwater, and saltwater (half, same, and twice the concentration of seawater) used to produce the cement mortar. Then, these four types of mixing water were used to cure the mortar till the test ages (7 days and 28 days). The test results show that, at 7 days, the compressive strength of saltwater (half concentration) mixing and curing mortar incorporating BFS is the highest (78 MPa). The freshwater mixing and curing control mortar has the lowest compressive strength (36.2 MPa). At 28 days, the compressive strength of saltwater (twice concentration) mixing and saltwater (half concentration) curing mortar incorporating BFS is the highest (90.2MPa). The strength of the control mortar is 53.0MPa under the same curing water, which is still relatively low. It can be seen from this that the mixing and curing of saltwater are beneficial to improving the compressive strength of cement mortar. The freshwater mixing and saltwater (twice concentration) curing cement mortar incorporating 30% BFS can have a higher strength at 28 days.

Abstract: Cement composites such as mortars and concretes with electrically conductive properties, have different uses, such as electromagnetic shielding, electrical grounding, cathodic protection, vehicle traffic monitoring, and the detection of strains and cracks in buildings. However, for these composites to have their electrical conductivity increased, it is necessary to incorporate electrically conductive materials, such as metals and carbon. Nonetheless, such materials tend to be expensive, which makes the manufacture of the composite more expensive. In this sense, using waste materials can help reduce costs and minimize impacts on the environment. Therefore, cement mortars were produced in this research with waste of brake linings from heavy vehicles, which may contain metallic and carbon-based materials. The mortars produced had part of the sand replaced by up to 70% crushed waste, which was submitted for analysis of compressive strength and electrical impedance. Preliminary results showed a decrease in the impedance (showing a trend of increasing electrical conductivity) of mortars with brake lining waste compared to mortars without waste, as well as a decrease in compressive strength. Finally, the use of brake lining waste in the production of cement composites can help reduce the consumption of natural resources as well as minimize the disposal of waste in landfills, which in both cases contributes to the sustainability of the environment.

Abstract: Sustainability is very important to keep industrial growth and human development going. Concrete is the largest manufacturing material in the world and includes cement as a key bonding agent for developing strength. This paper shows that the use of chopped carbon fiber to reinforce cementitious materials improved the mechanical properties characteristics of the mortar. also proposes appropriate curing conditions for the chosen mortar. The experimental investigation was carried out to evaluate the mechanical properties of cement mortar, The study plan consists of four cement mortar mixtures with ratios include 0%, 0.25%, 0.5% and 1% of chopped carbon fiber volume fraction by weight % of cement using normal water for curing. The effects of four different methods of curing on the mechanical properties of cement mortar that have the best properties from adding chopped carbon fiber were investigated including the convectional curing. 1% carbon fibers showed the best improvement in the mortar strength.

Abstract: Cement mortar is the most commonly used cement-based material, which widely used in construction materials, filling materials and other fields. The aim of this paper is to study the compressive strength and wave velocity characteristic in different particle sizes and sand/cement ratio. The uniaxial compressive strength test and wave velocity test were carried out in different particle size and sand content of mortar samples, respectively. It was found that the compressive strength and wave velocity decrease with the increase of sand/cement ratio. It is interesting that compressive strength and wave velocity in all specimens gradually increases with the increase of particles sizes. The compressive strength of cement mortar is related to the wave velocity. In detailed, the compressive strength and wave velocity was fit to linear relationship. It could thus be used to predict the compressive strength of cement mortar by wave velocity.

Abstract: The paper summarises the results of experimental analysis focused on the maturity method. The method is used to determine the early-age compressive strength of concrete on a construction site to optimise the construction process. All presented calibration curves of different recipes were determined experimentally. Comparison of calibration curves shows effects of specific changes in the recipe on early-age compressive strength development of cement mortar. Investigated changes in the recipe are the following: use of different cement types from different sources, amount of cement, water-cement ratio, used fine aggregates, admixtures and additions. Besides mentioned comparison, the topic of accuracy and deviations is included. Deviations were investigated by repeated determination of calibration curves at a specific time after the creation of the first batch of the calibration curves. The experience acquired during cement mortar experimental analysis will be later used in upcoming experiments at a concrete supplier with different concrete recipes.

Abstract: The partial replacement of cement in concrete with the addition of granite Powder and nanosilica can help to increase the performance of cement mortar in concrete. The aim of the article is to investigate the performance of granite powder and nanosilica for the sustainable production of cementitious mortars. Mechanical, physical, and durability properties of these additives were first compared with the properties of cement. Afterward, a series of mortars modified with the addition of granite powder and nanosilica was made. The properties of the fresh mixes and the mechanical properties of the hardened composites were then tested. Finally, based on the obtained results, a cost analysis of the profitability of modifying cementitious composites with granite powder or flyash was investigated. We can conclude, it should be stated that both of these materials can successfully be used for the sustainable production of cementitious composites. This conclusion has a significant impact on the possibility of improving the natural environment by reducing the amount of cement production. More sustainable production of cement-based materials could enable CO₂ emissions to be decreased.