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Showing papers on "Mortar published in 2016"


Journal ArticleDOI
TL;DR: A review of the published enhancement methods for recycled concrete aggregate can be found in this paper, where the authors suggest that carbonation treatment is an efficient and feasible method for improving the mechanical properties and durability of recycling concrete aggregate.

647 citations


Journal ArticleDOI
TL;DR: In this paper, a review of ground granulated blast furnace slag (GGBFS) utilization and efficiency on the properties of mortar/concrete is presented, including workability, setting time, bleeding, rheological properties, slump loss, segregation resistance and early age cracking potential and finishability.

437 citations


Journal ArticleDOI
TL;DR: In this paper, the authors introduced a new rapid, relevant and reliable (R 3 ) test to predict the pozzolanic activity of calcined clays with kaolinite contents ranging from 0 to 95%.

296 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of different types and amounts of organic coatings applied to a carbon fabric could affect the bond behavior between fabric and mortar, and the effectiveness of coating treatments was studied by means of direct tensile, pull-off and shear-bond double-lap tests.
Abstract: The use of composite materials for repair and retrofit of structures has become a common use among the engineering community. Fabric Reinforced Cementitious Matrix (FRCM) is a composite material specifically designed for masonry and concrete rehabilitation and is becoming a viable alternative to FRP, whenever the project conditions do not allow the use of organic polymer based composites. FRCM is usually constituted by one or multiple plies of dry fabrics (carbon, glass, aramid, basalt or PBO fibers) embedded into an inorganic matrix. If a polymer is used to either cover or bond the fabric strands, such polymer does not fully penetrate and impregnate the fibers as it would for FRP. The purpose of this research work is to study how different types and amounts of organic coatings applied to a carbon fabric could affect the bond behavior between fabric and mortar. The effectiveness of coating treatments was studied by means of direct tensile, pull-off and shear-bond double-lap tests. Experimentation was carried out on different combinations of fabrics and mortars, by varying the levels of pre-impregnation of the fabric during its manufacturing. In addition, the use of a quartz sand layer applied to the fabric after impregnation was investigated. Experimental evidence shows a promising enhancement of the bond between fabric and matrix and, therefore, of the entire system even with the use of low percentages of resin, depending on the type of mortar used.

179 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of nano-TiO2 (NT) and rice husk ash (RHA) on the strength and durability of mortars and found that 15% RHA and 5% NT can be considered as a suitable replacement regarding to the economic efficiency and hardened properties.

174 citations


Journal ArticleDOI
TL;DR: In this article, the current state of knowledge on durability of concrete and mortar made up of pozzolans as a partial replacement of Portland Cement is reviewed based on published documents and several potential studies have been suggested for the future research.

161 citations


Journal ArticleDOI
TL;DR: In this article, the authors present results from experimental studies on mechanical properties and thermal behavior of geopolymer mortar, prepared by alkaline solution activating metakaolin and fly ash blend.

156 citations


Journal ArticleDOI
TL;DR: In this paper, a review of agro-waste materials used as a partial replacement of fine aggregate in concrete is presented, where different properties of fresh and hardened concrete, their durability and thermal conductivity when admixed with agrowastes are reviewed.
Abstract: High demand of natural resources due to rapid urbanization and the disposal problem of agricultural wastes in developed countries have created opportunities for use of agro-waste in the construction industry. Many agricultural waste materials are already used in concrete as replacement alternatives for cement, fine aggregate, coarse aggregate and reinforcing materials. This paper reviews some of the agro-waste materials, which are used as a partial replacement of fine aggregate in concrete. Different properties of fresh and hardened concrete, their durability and thermal conductivity when admixed with agro-wastes are reviewed. Agro-waste used in self-compacting concrete and mortar are also reviewed and their properties are compared. It has been seen that the agro-waste concrete containing groundnut shell, oyster shell, cork, rice husk ash and tobacco waste showed better workability than their counterparts did. Agro-waste concrete containing bagasse ash, sawdust ash and oyster shell achieved their required strength by 20% of replacement as fine aggregate, which were maximum among all agro-waste type concrete. Close relations were predicted among compressive strength, flexural strength, tensile strength, ultrasonic pulse velocity and elastic modulus of agro-waste concrete. Addition of bagasse ash as fine aggregate in mortar increased the resistance of chloride penetration whereas inclusion of cork in mortar showed better thermal resistance and improved cyclic performance. After the review, it is of considerable finding that more research is deserved on all fine aggregates replacing agro-waste materials, which can give more certainty on their utilization in concrete.

151 citations


Journal ArticleDOI
TL;DR: In this article, the effects of rubber sand on workability, setting time, bleeding, density, strength, impact energy, impact load, toughness, ductility, shrinkage, abrasion resistance, freeze/thaw resistance, fire resistance, thermal insulation, carbonation resistance, corrosion resistance, water absorption, porosity, chloride ion penetration, resistance to aggressive environmental, energy absorption, sound absorption, electrical resistance and cracking resistance of rubberised mortar/concrete were reviewed.
Abstract: Currently, the need to incorporate recycled materials such as rubber in building products is becoming more important than ever before. The use of waste rubber in mortar/concrete mixtures creates landfill avoidance and decreases the depletion of virgin raw materials. Waste rubber can be used as a part of fine aggregate, coarse aggregate or both aggregates. It can be used as an additive to Portland cement (PC). This paper presents an overview of the previous researches carried out on the use of waste rubber as partially or fully natural fine aggregate replacement in traditional mortar/concrete mixtures based on PC. The effects of rubber sand on workability, setting time, bleeding, density, strength, impact energy, impact load, toughness, ductility, shrinkage, abrasion resistance, freeze/thaw resistance, fire resistance, thermal insulation, carbonation resistance, corrosion resistance, water absorption, porosity, chloride ion penetration, resistance to aggressive environmental, energy absorption, sound absorption, electrical resistance and cracking resistance of rubberised mortar/concrete were reviewed.

145 citations


Journal ArticleDOI
TL;DR: In this paper, the characteristics of recycled aggregates retrieved from crushed old concrete obtained from demolished structures, and five different presoaking surface treatment method and silica fume impregnating method to improve the properties of the recycled aggregate and its effect on recycled aggregate concrete (RAC).

138 citations


Journal ArticleDOI
TL;DR: In this paper, the differences of effect of silica fume in paste, mortar and concrete were studied by determining the non-evaporable water content of pastes, measuring the compressive strengths of pasted, mortars and concretes containing 5% and 10% raw silica Fume, respectively, with water-to-binder ratios (W/B) of 0.29 and 0.24 and investigating the properties of interfacial transition zone between hardened paste and aggregate.

Journal ArticleDOI
TL;DR: In this article, the feasibility of incorporation of a fine fraction of recycled aggregates coming from construction and demolition waste in cement-based masonry mortar fabrication was studied, and the results of the dosages study suggest the possibility to replace 100% of natural sand with analyzed recycled aggregate.

Journal ArticleDOI
TL;DR: In this article, a mixture of mortar and concrete mixes with micro-encapsulated phase change materials (PCMs) was used as part replacement of fine aggregates and assessed for improved thermal performance.

Journal ArticleDOI
TL;DR: In this article, three-point bending tests and optical microscope analyses are performed on a cement mortar reinforced with 3D printed fibers made of polymeric and metallic materials, which exhibit different surface morphology and roughness.
Abstract: We employ additive manufacturing technologies for the design and fabrication of novel reinforcing elements of cement mortars. Three-point bending tests and optical microscope analyses are performed on a cement mortar reinforced with 3D printed fibers made of polymeric and metallic materials, which exhibit different surface morphology and roughness. Experimental and analytical results highlight that the shear capacity, flexural strength and fracture toughness of the examined materials greatly depend on the design and the material of the reinforcing fibers. Specimens reinforced with high surface roughness fibers exhibit shear failure and high interfacial bond strength, while unreinforced specimens and specimens reinforced with smooth fibers exhibit flexural failure and limited interfacial bond strength. We observe that mortar specimens reinforced with titanium alloy Ti6Al4V fibers exhibit load carrying capacity more than twice as high as specimens reinforced with photopolymeric fibers.

Journal ArticleDOI
TL;DR: In this paper, an experimental study was carried out to evaluate the fluidity, flexural strength, compressive strength, shrinkage, bond strength and wear resistance of self-leveling mortar prepared with original phosphogypsum.

Journal ArticleDOI
TL;DR: In this article, the effects of incorporating two supplementary cementitious materials: rice husk ash (RHA) and nano-alumina (NA) in polypropylene fiber reinforced cement mortars were investigated.

Journal ArticleDOI
TL;DR: In this article, two types of multi-walled carbon nanotubes (pristine, p-CNT and functionalized, f -CNT) were dispersed in water by sonication and then added to cement mortar.
Abstract: In this study, two types of multi-walled carbon nanotubes (pristine, p-CNT and functionalized, f-CNT) were dispersed in water by sonication and then added to cement mortar. The purpose of this study was to characterize the dispersion degree of the CNTs in aqueous suspension and to investigate whether achieving dispersion in water would also result in dispersion inside mortar. Dispersion of the CNTs in water was investigated by means of UV–vis spectroscopy, using different CNT concentrations and sonication durations. Dispersion of the CNTs in cement mortar was investigated by measuring the compressive and flexural strength and fracture toughness as well as the microstructural characterizations of scanning electron microscopy and mercury intrusion porosimetry. The effects of the CNT addition on drying shrinkage and cement hydration were also investigated for cement pastes. The results of UV–vis spectroscopy showed that by increasing the sonication time to 120 min, the dispersion degree of the f-CNT suspension increased progressively, while for p-CNT, a maximum was reached with 60 min of sonication. The compressive and flexural strength and fracture toughness of mortars containing f- and p-CNTs were not significantly improved either by increasing the amount of CNT or imposing sonication in mixing water. High CNT dispersion in cement matrix was not equally obtained by utilizing highly dispersed CNT suspension. Sonication of f- and p-CNT led to a remarkable deceleration of cement hydration in the first hour of hydration and drying shrinkage of the cement composites was found to be reduced by f- and p-CNT addition.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the impacts of three factors on the heavy metal leaching content, and the curing time on the strength of mortar specimens blended with MSWI fly ash.
Abstract: Cement solidification technology can effectively reduce environmental pollution caused by municipal solid waste incineration (MSWI) fly ash. The present study aimed at investigating the impacts of three factors on the heavy metal leaching content, and the curing time on the strength of mortar specimens blended with MSWI fly ash. The factors are the quantity of cement, the PH value of leaching liquid and the vibrating leaching time. And the fly ash used in experiments is sampled from Harbin MSWI power plant. The results demonstrated that the leaching concentration of heavy metal of MSWI fly ash reduced significantly after being blended with cement, especially for Pb and Cd. As the PH value of the leaching liquid increased, the heavy metal leaching concentration quickly cut down to a very low value. The heavy metal leaching concentration significantly increased with leaching vibrating time in range of 16 h or 32 h. But conversely, both flexural strength and compressive strength of mortar specimens obviously dropped and the curing time of mortar specimens was delayed due to the addition of MSWI fly ash. Fortunately, the strength of mortar exceeds strength requirement of non-main building and base structure concrete and it can be recycled as base structure material.

Journal ArticleDOI
TL;DR: In this paper, the authors developed thermally-stable materials based on slag, fly ash, and metakaolin compared to portland cement mixtures by using a hierarchical approach to material design, where X-ray diffraction (XRD) characterized the mineralogy that coupled to higher length scale experiments using thermogravimetric analysis (TGA) for determining the materials thermal stability.

Journal ArticleDOI
TL;DR: In this paper, the compressive strength of a geopolymer mortar with a liquid binder (L/B) ratio of 1 was determined and six different mixtures with an L/B ratio in the range from 1 to 0.5 were prepared.
Abstract: In this study, geopolymer mortars were prepared by replacing blast furnace slag (BFS) based mixtures with coarse fly ash (FA) in different proportions. The aim of this study was to build a geopolymer mortar design for high temperatures using constant NaOH molarity (M) and constant curing temperature. In addition to 14 M NaOH solution and BFS as the binder material at a 60 °C curing temperature, double binder mixture ratios were prepared adding 25%, 50% and 75% FA. Geopolymer mortars with a liquid binder (L/B) ratio of 1 were subjected to oven curing for 5, 24, 48, 168 h. After physical and mechanical tests, the samples with the highest compressive strength were determined and six different mixtures with an L/B ratio in the range from 1 to 0.5 were prepared in order to increase the compressive strength of the samples in question. The physical and mechanical tests were repeated for the new samples. After the tests, the mortar sample with the highest compressive strength and its high temperature behavior was determined. For this purpose, the mortar sample with the highest compressive strength was subjected to temperatures of 200, 400, 600, 800 and 1000 °C, and changes in the physical and mechanical properties was analyzed. As a result of the experiments, the highest flexural strength value (3.6 MPa) was obtained from the mortar samples with a 25% BFS content subjected to curing for 5 h. The highest compressive strength values (27.3 MPa) were obtained from the mortar samples with a 100% BFS content subjected to curing for 48 h. In terms of compressive strength, the optimization of the L/B ratio resulted in a 28% increase (0.7) and this way, 35.1 MPa was achieved. Following the high temperature tests, 400 °C and 600 °C were determined as critical temperatures for changes in mechanical properties and changes in physical properties, respectively. However, the geopolymer mortars lost around 58% of strength at 1000 °C which is the final temperature.

Journal ArticleDOI
TL;DR: In this paper, a mortar based on SiO 2 aerogel particles has been successfully prepared, and the results show that when the dosage was 0.2, 0.05% and 1% respectively, the thermal conductivity was the lowest (0.0859 W/m·K).

Journal ArticleDOI
TL;DR: In this article, the possibility of using granulated blast-furnace slag as partial or full natural silica sand replacement in alkali-activated slag (AAS) mortar was investigated.

Journal ArticleDOI
TL;DR: In this paper, the authors present a study on the expansion due to alkali-silica reaction (ASR) of mortar bars containing different percentages of granulated ferronickel slag aggregates originated from garnierite ore.

Journal ArticleDOI
TL;DR: In this article, the corrosion behavior of steel in different room temperature cured alkali-activated fly ash mortars exposed to a chloride solution was monitored by polarization resistance and corrosion potential measurements and the results were interpreted in the light of a complete microstructural, mechanical and chemical characterization of the mortars.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated combined treatments applied on bottom ash fines (BAF) to increase their reactivity and compared the treated BAF with both untreated BAF and cement, and its contribution to cement hydration.
Abstract: Untreated municipal solid waste incineration (MSWI) bottom ash fines (0–2 mm) have poor pozzolanic properties, and contain substances which can pose an environmental risk (e.g. heavy metals and salts). This study investigates combined treatments applied on bottom ash fines (BAF) to increase their reactivity. The treated BAF is compared with both untreated BAF and cement, and its contribution to cement hydration is investigated. Additionally, the utilization of the treated BAF in mortar as cement replacement is tested. Finally, the leaching properties of mortars containing treated and untreated BAF are estimated. According to the results obtained, the 28-day compressive and flexural strengths of mortar with 30% treated bottom ash are about 16% and 6% lower than the reference mortar, respectively. The leaching of contaminants from the crushed mortars with BAF are well under the limit values imposed by Dutch legislation.

Journal ArticleDOI
TL;DR: In this paper, the improvement of thermal insulation behavior of concrete and mortar plastic compounds is presented by adding to mortar and concrete five different percentages of two types of plastic waste (polyethylene and PVC residues coming out of electric cable protective sheath).

Journal ArticleDOI
TL;DR: In this paper, a partial replacement of Ordinary Portland Cement (OPC) by 10% and 20% of untreated sugarcane bagasse ash (UtSCBA), and by 10%, 20%, and 20%, untreated fly ash, was used practically “as received”.

Journal ArticleDOI
TL;DR: In this article, the authors determined the physical and chemical effects of RHA on the properties of mortar including mechanical properties (compressive strength, flexural strength) durability properties (water absorption, porosity) and microstructure development.

25 May 2016
TL;DR: The effects of mixing procedure, testing procedure and relative proportions of constituent materials on the rheology of fresh mortar, as measured by the ViscoCorder, have been studied.
Abstract: The effects of mixing procedure, testing procedure and relative proportions of constituent materials on the rheology of fresh mortar, as measured by the ViscoCorder, have been studied. Mortar shows...

Journal ArticleDOI
TL;DR: In this paper, a new geometrical model is described, which can simulate the composite structures of mortar and concrete with real-shape aggregates, either directly or statistically taken from real particles, using a spherical harmonic expansion.
Abstract: The composite geometrical structure of mortar composites can be represented by a model consisting of sand embedded in a cement paste matrix and the structure of concrete by gravel embedded in a mortar matrix. Traditionally, spheres have often been used to represent aggregates (sand and gravel), although the accuracy of properties computed for structures using spherical aggregates as inclusions can be limited when the property contrast between aggregate and matrix is large. In this paper, a new geometrical model is described, which can simulate the composite structures of mortar and concrete with real-shape aggregates. The aggregate shapes are either directly or statistically taken from real particles, using a spherical harmonic expansion, where a set of spherical harmonic coefficients, a nm , is used to describe the irregular shape. The model name of Anm is taken from this choice of notation. The take-and-place parking method is employed to put multiple irregular particles together within a pre-determined empty container, which becomes a representative volume element. This representative volume element can then be used as input into some kind of computational material model, which uses other numerical techniques such as finite elements to compute properties of the Anm composite structure.