Density Of Mortar Research Articles

Using TiO2 nanoparticles as a SO2 catalyst in cement mortars

Titanium dioxide (TiO2) has been used in building materials to produce products that do not require major maintenance and also contribute to improve air quality and extend the life of buildings. Thus, this research evaluated the effects of incorporation of this substance into cement mortars in the process of degradation of sulfur dioxide (SO2), one of the largest atmospheric pollutants. Mortars were developed at a weight ratio of 1:3 (cement: sand), incorporating 2.5%, 5%, 7.5% and 10% of TiO2 relative to the cement weight. Mortars were evaluated in their fresh state (consistency and bulk density) and hardened (dry bulk density, water absorption by capillarity, open porosity and flexural and compressive strength). The samples were exposed to an accelerated aging SO2 (pollutant) chamber, then moistened and exposed to ultraviolet radiation. For this exposure of the samples, two Light Emitter Diodes (LEDs) with wavelengths covering the UV-A range were used: UV (380–420 nm) and blue (420–493 nm). Fourier Transform Infrared measurements were also performed in three stages, which were: (1) before contamination, (2) after SO2 contamination and (3) after radiation exposure. The nano TiO2 incorporation in the mortars contributed to the increase in open porosity and favored the increase in dry bulk density of mortars this was due to the filler effect. In addition, there was an increase in both the compressive strength and the flexural strength for mortars with addition, compared with the reference mortar. It can be concluded that the incorporation of TiO2 improved the physical, mechanical and photocatalytic properties, and enabled the decontamination of mortars due to the action of the SO2 pollutant.

An Experimental Study on Water Permeability of Architectural Mortar Using Waste Glass as Fine Aggregate.

This paper investigates the water permeability, consistency and density of architectural mortar with various contents of glass sand as fine aggregate. To reduce the effect of alkali-silica-reaction (ASR), metakaolin (MK) was used as supplementary cementitious material (SCM) instead of a component of white cement. The microstructure of glass sand mortar was visualized by means of scanning electron microscope (SEM) images. The experimental results showed that the permeability of the mortar increased with the glass sand, reaching its maximum at about 60–80% glass sand content. The optimum MK content varied with the content of glass sand, and higher content of MK was required for 60% glass sand. In addition, the consistency and density of mortar had a negative correlation with the increase of glass sand.

Study on EPS thermal insulation mortar prepared by magnesium oxychloride cement

In this paper, a composite thermal insulation mortar was prepared with magnesium oxychloride cement and polystyrene (EPS) particles. The influence of EPS particles content on the mechanical strength, density and thermal conductivity of composite thermal insulation mortar was studied. Also, the effect of fly ash on the density and thermal conductivity of the mortar was researched. It was shown that: (1) Generally, EPS particles could reduce the compressive strength, flexural strength, density and thermal conductivity of the mortar. The 28 days compressive strength and 28 days flexural strength decreased by 93.3 % and 81.3 % respectively, with the content of EPS particles from 0 % to 0.486 %. Also the density of the mortar was reduced from 2043 g/dm3 to 805 g/dm3, and the thermal conductivity was fell from 0.4093 W/(m·K) to 0.2191 W/(m·K). (2) Small amounts (less than 5.487 %) of fly ash could increase the density and thermal conductivity. However, when the content of fly ash was more than 5.487 %, the density and thermal conductivity of thermal insulation mortar were significantly reduced.

An enhanced mix design method of self-compacting concrete with fly ash content based on paste rheological threshold theory and material packing characteristics

This study investigated an enhanced mix design method of self-compacting concrete (SCC) with fly ash (FA) content based on paste rheological threshold theory and material packing characteristics. Seven SCC mixes with FA replacement levels of 0%, 10%, 20%, 30%, and 40% by volume were conducted to investigate the effect of FA on the rheological properties of SCC. A basic water demand experiment of mortar was designed to obtain the packing density of mortar. Furthermore, the equivalent packing density was defined and calibrate to quantify and represent the effect of FA. The yield stress and plastic viscosity threshold formula were modified based on the equivalent packing density. And the bilinear interpolation method was used to analyze the paste and SCC results. Besides, twenty seven SCC series with different water to cement ratio, FA replacement levels were conducted to verify the applicability of the enhanced method. The results show that, the relative accuracies of the improved method are higher than 83%, whereas those of the initial method are no greater than 60%.

Estudio del comportamiento de los morteros reciclados frente al ruido de impacto

En la actualidad existe una amplia gama de sistemas y materiales que se emplean como atenuadores del ruido de impacto, ofreciendo buenas prestaciones a la hora de evitar la transmisión de vibraciones a través de los forjados. En este trabajo, se han elaborado placas de mortero de cuatro centímetros de espesor con cuatro tipos de árido diferentes combinados con distintas tipologías de aislamiento. Aprovechando la menor densidad de los morteros elaborados con árido reciclado, se ha llevado a cabo una investigación en la que se propone sustituir el 100% del árido natural por árido reciclado para la fabricación de morteros empleados en el sistema de losa flotante, ya que ofrecen una solución más eficiente desde el punto de vista acústico. Los morteros elaborados con áridos reciclados de cerámica y mixto los que presentan la solución óptima para atenuar impactos producidos sobre la superficie, reduciendo hasta en un 20% la velocidad de transmisión de impactos frente a sus homólogos elaborados con árido natural.

Packing density of mortar containing polypropylene, carbon or basalt fibres under dry and wet conditions

The addition of fibres to concrete can significantly improve the hardened properties but may adversely affect the fresh properties. Apart from entangling with each other to hinder the flow of fresh concrete, the fibres might also interfere with the packing of the solid particles in the concrete. However, the packing density of fibre reinforced concrete made with flexible fibres was rarely measured and thus the effects of flexible fibres on the packing density are still not well understood. Herein, the packing densities of mortar containing polypropylene, carbon or basalt fibres under dry and wet and with and without superplasticizer added conditions were measured and compared to evaluate the effects of the flexible fibres on the packing density. It was found that the packing density of mortar containing these fibres is much higher under wet condition than under dry condition and that the fibre content, fibre length and superplasticizer all have certain influences on the packing density. Based on the test results, best-fit equations revealing the variations of the packing density with the fibre factor under different conditions are derived.

Effect of Rice Husk Ash Silica as Cement Replacement for Making Construction Mortar

Rice husk ash (RHA) is used as a replacement to cement to produce mortar. The effect of 5, 10, and 15wt% addition to the density and compressive strength of mortar is investigated. It was found that with the increasing addition of RHA causes the decrease of compressive strength and density of mortars. Compressive strength of mortar drops with addition of RHA, from a value of 42 MPa of no RHA addition, to 24 MPa of 15wt% RHA addition. Reduction in compression strength may be due to the decrease in density, which arises from porous RHA. This is more dominant in mortar made from addition of RHA without prior acid treated. Carbon residue and impurity in RHA further reduce the compressive strength of mortar. In addition, this research validate the use of a more environmentally friendly citric acid for partially removal of oxide impurities prior to burning the rice husk.

Influence of Graphene Nanosheets on Rheology, Microstructure, Strength Development and Self-Sensing Properties of Cement Based Composites

In this research, Graphene oxide (GO), prepared by modified hammer method, is characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) Spectrometry and Raman spectra. The dispersion efficiency of GO in aqueous solution is examined by Ultraviolet–visible spectroscopy and it is found that GO sheets are well dispersed. Thereafter, rheological properties, flow diameter, hardened density, compressive strength and electrical properties of GO based cement composite are investigated by incorporating 0.03% GO in cement matrix. The reasons for improvement in strength are also discussed. Rheological results confirm that GO influenced the flow behavior and enhanced the viscosity of the cement based system. From XRD and Thermogravimetric Analysis (TGA) results, it is found that more hydration occurred when GO was incorporated in cement based composite. The GO based cement composite improves the compressive strength and density of mortar by 27% and 1.43%, respectively. Electrical properties results showed that GO–cement based composite possesses self-sensing characteristics. Hence, GO is a potential nano-reinforcement candidate and can be used as self-sensing sustainable construction material.

Water Absorption and Hydration Products of Metakaolin Modified Mortar

The compressive strength, water absorption and hydration products of mortar with metakaolin addition were characterized by a range of techniques to evaluate the effect of metakaolin on the properties and hydration of mortar. Metakaolin is more effective on the improvement of compressive strength of mortar after curing for 7 days, due to the refinement of pore structure and pozzolanic reaction between metakaolin and calcium hydroxide. Water absorption of mortar was reduced by introducing metakaolin, especially in the very early age, due to the optimization of packing density of mortar by superfine metakaolin particles. There is no correlation between compressive strength and water absorption of mortar due to the differences between mechanisms affecting the compressive strength and water absorption of mortar by metakaolin. The hydration products of mortar without metakaolin were Portlandite and ettringite. Additional hemicarboaluminate and monocarboaluminate were identified in mortar with metakaolin addition. Metakaolin addition reduced the calcium hydroxide content due to the pozzolanic reaction.

The effect of replacing sand by iron slag on physical, mechanical and radiological properties of cement mortar

In the present study, the effects of replacing sand by high percentages of basic-oxygen furnace slag on the compressive strength, bulk density and gamma ray radiation shielding properties of mortar have been investigated. Cement mortar of mix proportion 1:3 including various percentages of iron slag was designed. The percentages of replacement were 0%, 40%, 80% and 100% by weight of fine aggregate. Mortar mixes were prepared with water cement ratio of 0.44 and cured in potable water for 90days. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised 137Cs and 60Co radioactive elements with photon energies of 0.662MeV for 137Cs and two energy levels of 1.17 and 1.33MeV for the 60Co. Likewise, half value layer (HVL), tenth value layer (TVL) and the mean free path (mfp) for the tested samples were measured. Results of this investigation indicated that the strength properties of mortars increased significantly upon replacing sand partially by iron slag. It was also observed that the inclusion of iron slag as partial replacement with fine aggregate enhances the bulk density of mortar. On the other hand, full sand replacement by iron slag has significant effects on shielding efficiency in thick shields, as it reduces the capture gamma rays better than normal mortar incorporating sand.

The effect of replacing sand by iron slag on physical, mechanical and radiological properties of cement mortar

In the present study, the effects of replacing sand by different percentages of basic-oxygen furnace slag on compressive strength, bulk density and gamma ray-radiation properties of mortar have been investigated. Replacement percentages were 0, 40, 80 and 100% by weight of used aggregate. Likewise, linear and mass attenuation coefficients, half-value and tenth-value layers in addition to mean free path for the tested samples were measured. The results indicated that the strength properties of mixtures increased significantly upon replacing sand partially by iron slag. It is also revealed that the inclusion of iron slag as a partial replacement to sand enhances the bulk density of mortar. On the other hand, the replaced fine slag sample at level 100% has significant effects on shielding efficiency in thick shields, as it reduces the capture gamma-rays better than the conventional mortar.

Study on the lightweight hydraulic mortars designed by the use of diatomite as partial replacement of natural hydraulic lime and masonry waste as aggregate

In order to increase energy and resources utilization efficiency, and to find hydraulic mortars with improved properties, in this paper we employed diatomite as partial replacement of natural hydraulic lime NHL2 (NHL) and masonry waste powder (MWP) as aggregate in the preparation of mortars. Diatomite was used at 0%, 10% and 20% replacement by weight for NHL2 and the mortars were designed with different water binder ratios (w/b). The physical, mechanical, and anti-aggressive properties such as freeze and thaw, and acid and sulfate resistance properties of mortars were tested after 14, 28 and 90days of curing. The introduction of diatomite reduced the density of mortars, and it also reduced the total amount of raw materials, especially the amount of NHL, to prepare same volume of mortars. Diatomite replacement generally enhanced the compressive and flexural strength of hydraulic mortars. The enhancement mainly happened after 14days of curing when pozzolanic effect was noticeable. Diatomite replacement percentage and w/b influenced porosity, compactness and strength of mortars. There existed optimal diatomite replacement percentage and w/b for mortars to attain largest strength. The introduction of diatomite improved acid and sulfate resistance of mortars greatly. All the hydraulic mortars studied in this paper can still well develop strength under freeze and thaw condition.

Mechanical Properties and Durability of CNT Cement Composites.

In the present paper, changes in mechanical properties of Portland cement-based mortars due to the addition of carbon nanotubes (CNT) and corrosion of embedded steel rebars in CNT cement pastes are reported. Bending strength, compression strength, porosity and density of mortars were determined and related to the CNT dosages. CNT cement paste specimens were exposed to carbonation and chloride attacks, and results on steel corrosion rate tests were related to CNT dosages. The increase in CNT content implies no significant variations of mechanical properties but higher steel corrosion intensities were observed.

Use of waste glass as sand in mortar: Part I – Fresh, mechanical and durability properties

In this study, mortar made with waste glass as fine aggregates was investigated for its suitability for construction use. A reference mortar mixture was proportioned according to ASTM C 109 and the fine aggregates were replaced by waste glass particles by 0%, 25%, 50%, 75% and 100%, by mass, to study its effect on the properties of mortar. For each mixture, four types of glass sand, namely, brown, green, clear and mixed color glass, were used. Test results indicated that use of waste glass particles as fine aggregates would reduce the flowability and density of mortar, but increase its air content. Except drying shrinkage, the mechanical properties were compromised due to micro-cracking in glass sand and weakened bond with the cement paste. However, durability was enhanced, especially in terms of the resistance to chloride ion penetration. Accelerated mortar bar tests to ASTM C 1260 indicated that green and brown glasses were non-reactive while clear glass was potentially deleterious, with regards to alkali–silica reaction.

Properties of High-Strength Flowable Mortar Reinforced with Palm Fibers

This study was conducted to determine some physical and mechanical properties of high-strength flowable mortar reinforced with different percentages of palm fiber (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% as volumetric fractions). The density, compressive strength, flexural strength, and toughness index were tested to determine the mechanical properties of this mortar. Test results illustrate that the inclusion of this fiber reduces the density of mortar. The use of 0.6% of palm fiber increases the compressive strength and flexural strength by about 15.1%, and 16%, respectively; besides, the toughness index (I5) of the high-strength flowable mortar has been significantly enhanced by the use of 1% and more of palm fiber.

Influence of Species of Manufactured Sand on Basic Performances of Mortar

The influences of sand-cement ratio on bulk density, fluidity, compressive strength, flexural strength of mortar of river sand, limestone manufactured sand (MA), quartzite MA, granite MA were studied compresively in the paper. The results show that bulk density of mortar reaches to maximum if sand-cement ratio of mortar of river sand is 2.73 and the ratios of mortar of manufactured fine sands are all 3.0. The fluidity of mortars of river sand and limestone MA are better than those of quartzite MA and granite MA. Sand-cement ratios of mortars with maximum strength are equal to that with maximum bulk density. The sequence of compressive strength is limestone MA, quartzite MA, river sand, granite MA from high to low, and that of flexural strength is limestone MA, quartzite MA, granite MA, river sand.

Pozzolanic Activity of Ceramic Polishing Powder as Cementitious Material

The major industrial by-product largely generated in southern China is ceramic polishing powder (PP) produced from ceramic industries. In this paper, gross of silicon and aluminum dissolved from polishing powder and fly ash were studied by alkali dissolve experiments, pozzolanic activity of PP and fly ash were studied as well by determining chemical combined water and fast strength experiments. Results show that the cement mortar strength active index of PP is up to 82%. The average size of PP is 6.31 um; the fine granule of PP fills in the pore of mortars and improves the compressive strength of mortars. Microstructure of mortars added PP demonstrates that hydration gel is close-grained, dense and reticular. It reveals that “the granule domino effect” enhance the density of mortars added PP and conduce to the high compressive strength. Polishing powder can be used as cementitious material, especially the quality of early stage is higher than that of fly ash. Gross of vitreous phase is not the single factor to determine pozzolanic quality of polishing powder, ability of alive silicon and aluminum responding to Ca(OH)2 is one of the most important impact.

Fabrication Characteristics and Strength of Polymer-Impregnated Concrete Polymerized by Accelerated Electron

Since the accelerated electron has by far a higher dose rate than gamma-rays, the electron polymerizing method is more suitable for the efficient fabrication of polymer-impregnated concrete (PIC) with a thin cross section. However, there are few published papers on the manufacturing process of PIC polymerized by electron beam.This experiment was carried out to investigate the effects of density of cement mortar, dose rate of electron beam (4MeV), total exposure dose and other factors which have influences upon the strength of MMA-PIC. The density of mortar, size of cross section of mortar specimens, dose rate of electron, total exposure dose and irradiating time interval were varied respectively as follow; ρ=1.55∼3.13g/cm3 (the kinds of aggregates in cement mortar used are perlite, artificial light weight aggregate, normal river sand and iron sand), t=3.5∼40mm in thickness, 0.55 or 1.10 Mrads/sec, 12.5∼100 Mrads per face, and 15∼60sec/cycle.The test results of mechanical strength of PIC show that the optimum total exposure dose is about 40Mrads at 0.55Mrads/sec rate and 50Mrads at 1.1Mrads/sec in the ordinary mortar. It is also shown that the impregnation depth from the surface of specimen has a linear relation with the density of cement mortar, and that its depth is about 1cm in conventional mortar.

Thermal Conductivity and Strength of Vermiculite Mortar

The properties of vermiculite mortar made of the vermiculite from Fukushima, Japan, were discussed. The following tests were carried out on the insulating mortar samples cured in damp air: thermal conductivity, bulk density, compressive strength, tensile strength and modulus of rupture. By means of hand mixing, the expanded vermiculite (temperature of firing: 600°C) and commercial portland cement were mixed until the resultant mass had a uniform color; water (mixed with the neutralized solution of vinsol resin) was then added, and the batch was mixed for about 5 min to have a unifom consistency. From the data presented, the following results were obtained: (a) The bulk density of mortar decreased as the vermiculite content increased. (b) The lower-density mortars had lower strength but higher insulation value. (c) The effect of vermiculite content on thermal conductivity was greater in the range of 1:1-4 than in the range of 1:4-9 (cement: vermiculite); the rate of decrease in the conductivity with the increase of vermiculite content changed abruptly at about 1:4 mixture. (d) The effect of vermiculite content on strength was greater in the range of 1:0-1 mixtures than in the range of 1:2-4 mixtures; the curve in the range between 1:0-1 was steeper than in the range between 1:2-4. (e) For general construction purposes except the most unusual load conditions, the best mortar can be produced with a 1:4 mixture in accordance with Scholes and his coworkers' results for N. Carolina vermiculite. The properties of this mixture (by use of 475 litres of H2O per cu. m. of vemiculite and a mixing time of 5 min) after 28 days were as follows: Thermal conductivity, λt (kcal/m hr °C), at the mean temperature of t (°C): λt=0.0605+0.000191×t; bulk density: 0.902; compressive strength: 18kg/cm2; tensile strength: 7kg/cm2; modulus of rupture: 16kg/cm2 (f) The vermiculite mortars produced with 1:8-9 mixtures had higher insulation values than the loose-filled vermiculite (expanded at firing temperature of 700°C) pressed by 20 per cent. (g) Data on thermal conductivity, bulk density and strength of vermiculite mortars having various ratios of cement: vermiculite were given. (h) Expanded “Fukushima vermiculite” would be excellent as an aggregate for light-weight mortar with high insulation value.