Density Of Mortar Research Articles

Improving mortar properties using traditional ceramic materials ground to precisely controlled sizes

The present work investigates the impact of particle size reduction of traditional ceramic materials as partial substitutes for Portland cement in mortars. Ceramic brick, ceramic tile, and stoneware were selected, with three particle sizes (D50 of 1, 5, and 15 μm) achieved through grinding operations adapted to each material grindability. The reactivity of ceramic powders was assessed via dissolution in saturated lime solution. Mortars were prepared with 10 % and 20 % cement mass replaced by ceramic powders ground to each fineness. The packing density of mortars was evaluated using the Compressible Packing Model. Compressive strength was measured at 1, 3, 7, and 28 days, and pore size distribution was analyzed by mercury intrusion porosimetry. Results indicated that ceramic tile required less grinding energy than brick and stoneware. High-energy grinding slightly altered the crystalline structure and increased amorphous content, enhancing reactivity with lime. Increased cement replacement with finer ceramic powders (D50 about 1 μm) improved strength, increased mesopores (50 nm), and reduced pore size threshold, attributed to filler and pozzolanic effects. A multiple linear regression model effectively described the influence of various variables on mortar strength with the interaction terms demonstrating the complexity of the interplay of the variables.

Laboratory test and meso-scale discrete element modelling on creep behaviors of concrete

In this work, a series of concrete creep tests with different stress conditions were carried out by laboratory tests and the discrete element method (DEM). The instantaneous strain, creep strain, creep rate, as well as creep nonlinearity ratio were obtained by laboratory tests. Meanwhile, a DEM micromechanical model, including coarse aggregate with actual geometry, homogenized mortar, and interfacial transition zone (ITZ), was established and the validity of numerical results was verified by laboratory tests. On this basis, the mesostructure characteristics (i.e., contact force and force chain) were obtained by DEM micromechanical-based analysis. The results show that the creep strain increases with the increase of stress level and with the extension of load holding time, and the creep develops rapidly within 60 days and slowly after 60 days. As the applied stress level increases, the nonlinearity of creep strain becomes more obvious, all specimens achieve a stable nonlinear ratio after about 20 days. Meanwhile, the contact force in mortar and ITZ all tend to increase with the increase of stress level, resulting from the viscoelastic slippage in burger contact. The average contact force of ITZ is larger than that of mortar, and a difference of about 20% can be observed. The peak probability density of mortar occurs at fi/f‾ = 0.6–0.8, while that of ITZ occurs approximately at fi/f‾ = 0.5. By comparison with other models, the improved nonlinear viscoelastic-plastic creep model can well predict the creep behavior.

Study on physical and mechanical properties of cement asphalt emulsified mortar under track slab

PurposeDuring the construction process of the China Railway Track System (CRTS) I type filling layer, the nonwoven fabric bags have been used as grouting templates for cement asphalt (CA) emulsified mortar. The porous structure of nonwoven fabrics endowed the templates with breathability and water permeability. The standard requires that the volume expansion rate of CA mortar must be controlled within 1%–3%, which can generate expansion pressure to ensure that the cavities under track slabs are filled fully. However, the expansion pressure caused some of the water to seep out from the periphery of the filling bag, and it would affect the actual mix proportion of CA mortar. The differences in physical and mechanical properties between the CA mortar under track slabs and the CA mortar formed in the laboratory were studied in this paper. The relevant results could provide important methods for the research of filling layer materials for CRTS I type and other types of ballastless tracks in China.Design/methodology/approachDuring the inspection of filling layer, the samples of CA mortar from different working conditions and raw materials were taken by uncovering the track slabs and drilling cores. The physical and mechanical properties of CA mortar under the filling layer of the slab were systematically analyzed by testing the electrical flux, compressive strength and density of mortar in different parts of the filling layer.FindingsIn this paper, the electric flux, the physical properties and mechanical properties of different parts of CA mortar under the track slab were investigated. The results showed that the density, electric flux and compressive strength of CA mortar were affected by the composition of raw materials for dry powders and different parts of the filling layer. In addition, the electrical flux of CA mortar gradually decreased within 90 days’ age. The electrical flux of samples with the thickness of 54 mm was lower than 500 C. Therefore, the impermeability and durability of CA mortar could be improved by increasing the thickness of filling layer. Besides, the results showed that the compressive strength of CA mortar increased, while the density and electric flux decreased gradually, with the prolongation of hardening time.Originality/valueDuring 90 days' age, the electrical flux of the CA mortar gradually decreased with the increase of specimen thickness and the electrical flux of the specimens with the thickness of 54 mm was lower than 500 C. The impermeability and durability of the CA mortar could be improved by increasing the thickness of filling layer. The proposed method can provide reference for the further development and improvement of CRTS I and CRTS II type ballastless track in China.

Influence of macadamia nutshell particles on the apparent density and mechanical behavior of cement-based mortars

The production of cement mortar has resulted in significant environmental issues. Many scientists have attempted to reduce environmental pollution by using agricultural waste as a substitute for mortar raw materials. This study creatively investigated the physical and mechanical properties of the new green cement mortar made from macadamia nutshell(MN), including compressive strength, flexural strength, and apparent density of 7d, 14d, and 28d. The effects of cement-sand ratio (c/s), nutshell particle size, and MN substitution rate on cement mortar's physical properties were studied using three-factor and three-level orthogonal test design methods. The digital image correlation (DIC) technique was used to analyze the crack development of macadamia nutshell cement mortar (MNM) at different loading stages. The analysis of variance (ANOVA) showed that the cement-sand ratio was the most significant factor affecting the strength of MNM. In addition, adding MN can increase the compressive strength of the mortar compared to the control group. The apparent density of the mortar decreases with the increase of MN addition.

Statistical mix design method for self-compacting concrete with limestone fillers

This study presents a statistical mix design method for self-compacting concrete (SCC) with limestone fillers (LF) content that considers mortar rheological properties and material packing characteristics. The effect of LF on the rheological properties of SCC was investigated through seven SCC mixes with different LF replacement levels. A basic water demand experiment was designed to obtain the packing density of mortar, and the equivalent packing density was defined and calibrated to represent the effect of LF. The relative spread and relative flow formula were modified based on the equivalent packing density, and the bilinear interpolation method was used to analyses the mortar results.

Research on fire resistance of silica fume insulation mortar

Due to the increasingly tight energy supply situation, thermal insulation mortar is more and more widely used in the exterior wall insulation layer of buildings in various countries. However, the existing academic papers have less research on the key properties of thermal insulation mortar such as fire resistance and economic feasibility. Based on the previous research results, this study selected silica fume as an admixture to improve the comprehensive performance of insulation mortar. The goal is to develop a high-performance fireproof insulation mortar. This paper focuses on the fire resistance of the improved insulation mortar. The results show that silica fume mixed into the mortar will play a fine particle filling and hydration gelation cooperation, and the amount of silica fume mixed from 0 to 10% can significantly improve the bond strength and compressive strength of the mortar. For the thermal conductivity and dry density of mortar, there is a certain increase in the range of silica fume dosing from 0 to 4%, while the range of silica fume dosing from 4% to 10% decreases again. Silica fume has a favorable effect on improving the fire resistance of insulating mortar, and the mortar with 10% admixture of silica fume has about 28.30% lower mass loss rate after high temperature and about 14.73% higher relative compressive strength after high temperature after 28 days of maintenance. The final selected optimum admixture of silica fume is 10%, and the best ratio of raw materials is cement: aggregate: water: dispersible emulsion powder: fly ash: diabase rock powder: AOS foaming agent: gelatin: silica fume = 1: 1.67: 2: 0.045: 0.15: 0.225: 0.035: 0.02: 0.138.

Compressive strength, porosity, and density of mortar containing precipitated silica from Palm Oil Fuel Ash (POFA)

Palm Oil Fuel Ash (POFA) as an agro-industrial waste has potential applications in the construction industry. Using POFA to produce extracted precipitated silica is another step toward improving the performance of mortar and concrete with cost-effective biomass waste. This study investigates precipitated silica extracted from POFA as an additive for mortar. Mortar mixtures containing various percentages of precipitated silica (PS) and silica fume (SF) with 2%, 4%, and 6% by weight of cement were cast and studied. Compressive strength, porosity and density of the mortar at 28 days were tested to study the physical properties of the PCC-SP and PCC-SF mortars. The compressive strength of PCC-PS and PCC-SF mortars increased with the optimum 4% addition of silica. Precipitated silica mortar (PCC-PS) has lower strength, higher porosity, and similar density to the silica fume mortar (PCC-SF). However, the precipitated silica mortar has better strength, porosity, and density than the PCC mortar (control mix). The current findings suggest that the extracted precipitated silica can be used as a cost-effective additive from biomass waste to improve the performance of mortar and concrete.

Mix design method of granular packing for high performance concrete with natural pozzolans

This study presents an enhanced mix design method for High performance concrete (HPC) with Natural Pozzolans (NP) content that considers material packing theory. Seven HPC mixes with different NP replacement levels of 0, 5, 10, 15, 20, 25, 30% by volume were conducted to investigate the effect of NP on the rheological and mechanical properties of HPC. A basic water demand experiment was designed to obtain the granular packing and packing density of mortar. Furthermore, the equivalent packing density was defined and calibrated to represent the effect of NP, And the bilinear interpolation method was used to analyses the HPC properties. The results show that the relative accuracies of the improved method are higher than 15% to the initial method. The HPC mixtures with NP was also assessed and shown to be within the optimum area.

Physical and Mechanical Properties of Cementitious PVC Composites

This research studies the physical and mechanical properties of mortar composed of PVC plastic waste particles used as fine aggregate replacement material. PVC particles in quantities of 5%, 10%, 15%, 20%, 25%, and 30% by volume were used for sand fraction substitution. This quantity of PVC was used to formulate seven mixes with a cement content of 525 kg/m3 and a water-to-cement ratio (w/c) of 0.45. At 7 and 28 days, the compressive and splitting tensile strengths of the mortar's mechanical characteristics were evaluated. Additionally, the physical characteristics of density and absorption were investigated. The findings demonstrated that the mechanical properties and density of mortar containing PVC powder were minimized.

PROPERTIES OF FRESH AND HARDENED MORTARS WITH AIR-ENTRAINING AGENT

The influence of the air-entraining agent (AEA) on a density, the volume of entrained air of mortar mix and compressive strength of hardened mortar was studied in this article. Results show that the addition of AEA results in the reduction of water to cement ratio to provide the targeted flow and the density that depends on the volume of entrained air. The addition of AEA causes the decrease of the density of mortar (C:S=1:2) by 8,2% and the increase of the compressive strength by 13,9% after 28 days of hardening compared to the mortar (C:S=1:2) without AEA. The further increase of a sand content in a mortar (C:S=1:3) results in slight decrease of a density of fresh mortar and compressive strength. If C:S ratio is 1:4 the increase of the density and the compressive strength decrease is observed in comparison with the mortar with C:S=1:3. The obtained results show that properties of mortar incorporating AEA depend on its mix proportion.

Compressive and Flexural Strengths of Mortars Containing ABS and WEEE Based Plastic Aggregates.

The incorporation of plastic aggregates as a partial replacement of natural aggregates in cementitious materials is interesting in several ways. From a mechanical point of view, the partial substitution of sand with plastic aggregates could improve some properties (e.g., ductility, thermal insulation). This paper deals with the mechanical strength of mortars containing plastic aggregates as a partial replacement of sand. Part of the volume of sand in cement mortars is substituted with plastic aggregates which originate from WEEE (Waste from Electrical and Electronic Equipment) and consist of a mix of ABS (acrylonitrile-butadiene styrene), HIPS (high impact polystyrene) and PP (Polypropylene), or of monomaterial ABS from WEEE sorting. Three rates of replacement (by volume of sand) were tested: 10%, 15% and 30%. Mechanical tests were performed according to European standard EN196-1. The results show that compressive and flexural strength decrease with rate of replacement, but remain satisfactory for structural purposes. In addition, the density of mortar is reduced with the incorporation of plastic aggregates. The decrease of mechanical strength is mainly due to the weak bond between cement paste and plastic aggregates leading to the increase of porosity. Furthermore, it appears that mortars containing plastic aggregates could present a ductile rupture.

Role of recycled concrete powder as sand replacement in the properties of cement mortar

This paper investigates the properties of cement mortar containing recycled concrete powder (RCP) as sand replacement. Two types of model RCP prepared with designated water-to-cement (W/C) ratios in the laboratory, including recycled cement paste powder (RCPP) and recycled cement mortar powder (RCMP), were utilised in the mortar. The physical, mechanical and drying shrinkage properties of the mortars with various amounts of RCP were investigated, and their microstructure was characterised. The results indicate that increasing the RCP content increases the water demand and decreases the dry bulk density of mortars due to the inferior characteristics of RCP. Replacing sand by up to 10% RCPP prepared with various original W/C ratios or 20% RCMP has a negligible or slightly positive impact on the mechanical properties of mortars. This is mainly attributed to the decreased volume fraction of large capillary pores, air voids and total porosity, which overcomes the negative effects induced by RCP. Specifically, incorporating RCP can reduce the fraction of large voids through its filling effect and slightly promote hydration in mortars. Besides, the drying shrinkage of the mortars increases with the RCP replacement ratio due to the increased volume fraction of mesopores in the RCP mortars. However, an excessive amount of RCP increases the volume fraction of capillary pores and the total porosity of mortars due to the combined action of the decreased packing density and the high porousness of RCP particles, which subsequently decreases the mechanical properties and further increases the drying shrinkage of RCP mortars. In general, incorporating a proper amount of RCP as sand replacement can enhance the sustainability of mortars without compromising their mechanical properties.

Experimental Study with Plaster Mortars Made with Recycled Aggregate and Thermal Insulation Residues for Application in Building

The high demand for natural resources and increased industrial activity is driving the construction sector to search for new, more environmentally friendly materials. This research aims to analyse plaster mortars with the incorporation of construction and demolition waste (CDW) to move towards a more sustainable building sector. Three types of aggregates (natural, recycled concrete and recycled from ceramic walls) and two types of insulation waste (expanded polystyrene with graphite and mineral wool) have been added to the plaster matrix to evaluate its mechanical and physical properties and its suitability in the elaboration of prefabricated materials. The results show how plaster mortars made with recycled aggregates have higher mechanical resistance than conventional plaster without incorporating sand. The incorporation of crushed mineral wool residues improves the flexural strength of plaster mortars and their application in the execution of prefabricated panels. Likewise, the expanded polystyrene residues reduce the final density of mortars, improving their behaviour against water absorption and reducing the final thermal conductivity of plaster material.

Mechanical properties of eco-friendly cements-based glass powder in aggressive medium

Recycling glass waste for developing sustainable cementitious mortar and concrete have recently attracted increasing attentions for the construction industry. From another aspect, the nitrate-based environment due to chemical fertilizers has a significant effect on reinforced concrete and normal concrete by producing damages like its microstructure, corrosion of reinforcement. The major goal of this research work is to study the effect of Ammonium Nitrate (NH4NO3) on the unite weight and strength of glass mortar by performing experimental tests. In this article, eco-friendly mortar containing recycled glass powder (GP), as a replacement to cement, is submerged in NH4NO3 solutions. In total, 60 cement mortar mixtures were proportioned in this research work used GP passing sieves 200 µm. NH4NO3 solutions with 5, 10, and 20% concentration, and three different exposure periods 10, 30, and 60 days were applied. The experimental results showed that the effect of NH4NO3 on the density of mortar containing GP is less critical than that of conventional mortar. After 60 days of immersion in the solution with a concentration of 20% NH4NO3, the reduction in density of glassy mortar is less than that of ordinary mortar. Furthermore, the results indicated that the maximum compressive strength was attained at 10% replacement level of cement with GP by approximately 60 MPa after 60 days of immersion in NH4NO3 solution.

Studying some of mechanical properties and microstructure analysis for cement mortar using waste of depolymerized Polyethylene terephthalate by using bubble column technique

In this study, the density and compressive strength together with microstructural analysis of cement mortar by partial replacement of fine aggregate with the powder of Polyethylene terephthalate PET depolymerized by using bubble column technique has been studied. The powder of depolymerized Polyethylene terephthalate DPET was used with four different contents of 1%, 3%, 6%, and 9% by weight of fine aggregate. The destructive compressive strength test was prepared once it reaches ages 7 and 28 days of curing. Before that, the density of mortar determines at some samples for both ages. The lightweight modification mortar was set with ratios of 0.48 for water to binder and 1:2.75 for the cement to sand. After completing specific tests, the data of the result presented that the density of the modification cement mortars drops when using DPET powder as fine aggregate. The compressive strength of the modification cement mortars with DPET powder was slightly decreased with the increase of DPET powder percent. The microstructure of the modification cement mortar containing DPET powder showed that DPET particles plug the holes.

Improvement of mix design method based on paste rheological threshold theory for self-compacting concrete using different mineral additions in ternary blends of powders

This work investigates an improved mix design method based on paste rheological threshold theory for self-compacting concrete (SCC) with ternary blends powder materials. Six batches of SCC and their equivalent paste tests were first performed to test and verify the applicability of the initial mix design method with SCC contains LP (limestone powder) and FA (fly ash). The basic water demand experiments of mortar were used to obtain the packing density of mortar. A total of 21 SCC tests were then conducted to present an improved mix design method. Yield stress and plastic viscosity threshold formulas are modified based on material packing characteristics. The bilinear interpolation method was used to process paste and SCC results. Futhermore, a total of 36 SCC series were conducted to verify the applicability of the improved method. Prediction accuracy formula according to the figure area were introduced to assess the predictive effect of the improved method. Results show that the relative accuracies of the improved method are higher than 78%, while the initial method is no greater than 45%. This improved mix design method is still applicable with SCC contains both LP and FA.

Effect of aluminium sulphate Al2(SO4)3 treatment on paper waste as a fine aggregate partial replacement in lightweight cement mortar

In recent years there has been increasing interest in the use of recycled paper waste in the production of concrete to reduce environmental pollution. This study aims to investigate the use of raw paper waste to produce lightweight cement mortar and to study the effect of the aluminium sulphate treatment of raw paper waste on the compressive strength, absorption ratio and hardened density of mortar. This study used raw paper waste as a replacement for fine aggregate, with percentages of 5%, 10%, 15%, 20% and 30%. The same percentages were examined for the aluminium-sulphate-treated paper waste. The study aims to achieve a similar workability and fixed flow rate for all mixes; therefore, the water–cement ratios were changed for mixes containing paper waste to balance the water absorbed by the paper waste. The study found that the treatment of paper waste with aluminium sulphate helps to reduce the amount of water absorbed by the paper waste and also reduces the amount of water required to maintain its workability, with a higher paper-waste content requiring a larger water content to achieve a similar workability. It was found that the higher the paper-waste content, the lower the wet and dry densities. The compressive strength at both an early and mature age decreased with the increased content of paper waste. Finally, the treatment of paper waste with aluminium sulphate increases the early age compressive strength for similar replacement percentages of up to 19%.

Mechanical Properties of Mortar Using Polypropylene Fibers

In the present paper the behavior of mortar reinforced with polypropylene fibers was studied. Different percentages of polypropylene fibers such as 0, 0.2, 0.4, 0.6 and 0.8% as volumetric fractions were used. Different properties which are flowability, density, compressive strength, flexural strength and splitting tensile strength were evaluated for all mix combinations. The experimental results indicated that a reduction in flowability was obtained with increased polypropylene fibers content. Besides, it can be concluded that the incorporation of polypropylene fiber may significantly reduce the density of mortar. The use of low volume fraction of polypropylene fiber improves the mechanical properties of HPM. Thus, the use of 0.2% of such fiber increases compressive strength by about (4-10%), at various ages.

Properties of Alkali Activated Lightweight Aggregate Generated from Sidoarjo Volcanic Mud (Lusi), Fly Ash, and Municipal Solid Waste Incineration Bottom Ash.

Production of artificial lightweight aggregate (LWA) from industrial by-products or abundant volcanic mud is a promising solution to prevent damaging the environment due to the mining of natural aggregate. However, improvements are still needed in order to control the high water absorption of LWA and strength reduction in resulting concrete or mortar. Hence in this research, fly ash, municipal solid waste incineration bottom ash (MSWI BA), and Sidoarjo volcanic mud (Lusi) were employed as a precursor and activated using NaOH 6 M and Na2SiO3 in producing LWA. The influence of the type of the precursors on the physical properties of resulting LWA was investigated. The effect of replacing natural fine aggregate with the resulting LWA on the compressive strength and volume density of mortar was also determined. Finer particles, a high amount of amorphous phase, and low loss on ignition (LOI) of the raw material improved the properties of resulting LWA. Mortar compressive strength was decreased by 6% when replacing 16% by volume of natural fine aggregate with fly ash based LWA. Compared to the expanded clay LWA, the properties of alternative LWAs in this study were slightly, but not significantly, inferior. Alternative LWA becomes attractive when considering that expanded clay LWA requires more energy during the sintering process.

Lightweight Pumice Mortars with Polypropylene Fiber Reinforcement

The use of porous particles as aggregates in cementitious mixes presents advantages such as reducing dead load and assisting in thermal insulation of constructions. Pumice aggregates are most commonly used because they are cheap, natural and easily obtainable. However, there are also disadvantages such as brittle behavior and decrease in strength. In this study, 0, 1 and 2 vol% polypropylene fibers (PF) having 40 micrometer diameter were used in the production of mortars containing acidic (AP) and basaltic pumices (BP) in place of calcareous sand (CS), in order to overcome these challenges. In addition to mechanical properties (compressive, flexural and splitting tensile strength), physical properties (bulk density and capillarity) and morphology of mortars (scanning electron and optical microscopy) were also investigated. The results showed that bulk density of BP mortars was about 10% lower and that of AP mortars was about 15% lower than that of CS mortars. Flexural strength of BP and CS mortars were over 7 MPa, whereas that of AP mortars were in 4–6 MPa range. Addition of 1% PF improved the mechanical properties, whereas addition of 2% PF resulted in a decrease in strength in all mortar types. The highest 1-year compressive strength was obtained by the BP sample having 1% PP fiber. Furthermore, there was a strong relationship between the strength and bulk density of mortars.