Showing papers on "Mortar published in 2020"
TL;DR: In this article, the adaptive neuro-fuzzy interfacial systems (ANFIS) method was used to establish the artificial intelligence (AI) model to predict the fracture parameters of geopolymer/alkali-activated mortars.
136 citations
TL;DR: In this article, the quantitative relationship between the content of old attached mortar and the performance of recycled aggregate at the material level was analyzed. And three aspects of the performance prediction, application range and reinforcement method for RAs were illustrated in the article.
128 citations
TL;DR: In this paper, the effects of the setting time of the printed concrete and changes of the interlayer moisture were tested and the optimal polymer mortar that strengthened the interfaces most effectively was identified.
Abstract: The inherent weak interfaces between adjacent layers by the laminate stacking process of 3D concrete printing hinder this advanced technique for general engineering applications. In this study, polymer-modified mortars were fabricated to improve the weak interlayer bonding performances. The effects of the setting time of the printed concrete and changes of the interlayer moisture were tested. Both epoxy resin- and chloroprene latex-modified mortars were prepared and used as interlayer interface enhancement materials according to different interlayer intervals. The direct tensile and shear strengths of the polymer mortar-strengthened interfaces were tested and evaluated by the crossover test. Moreover, the effects of the moisture released from the surface of the cement-based composite materials on the interlaminar bonding properties and the enhancing mechanism of the epoxy resin- and chloroprene latex-modified mortars were simulated through molecular dynamics and density functional theory. The results demonstrate that the electrostatic interaction (Coulomb force) between the epoxy resin and calcium ions from hydrated calcium silicate counteracts the weakening effect of water molecules (surface moisture) on the interlaminar bonding, thus improving the interface bonding of printed concrete. The optimal polymer mortar that strengthens the interfaces most effectively was identified.
102 citations
TL;DR: In this paper, artificial neural networks (ANNs) are used to simulate and map the development of natural hydraulic lime (NHL5) mortars' characteristics, such as compressive strength, ratio of compressive to flexural strength (CS/FL) and consistency (CO), for selected mortar mix parameters.
97 citations
TL;DR: In this paper, the properties of high calcium fly ash geopolymer mortars containing natural fibers were investigated, and the addition of natural fiber (sisal and coconut fibers) as reinforcing materials resulted in significant improvement in tensile and flexural strength performances similar to the use of glass fiber.
95 citations
TL;DR: In this article, the incorporation of primary pulp and paper industry sludge waste, still in its liquid state, into cement and lime-based mortars was evaluated in terms of technological, durability and environmental performance of both liquid and dry incorporated mortars, as well as with reference control mortar without incorporation.
94 citations
TL;DR: In this paper, an additive mortar based on calcium sulphoaluminate (CSA) cement, cellulose fiber and limestone filler was proposed for application between layers, which permits extension of printing time interval and also caters for breaks in construction printing.
91 citations
TL;DR: In this article, a series of impact dynamic tests were conducted by a modified split Hopkinson pressure bar (SHPB) system to investigate the filling joint effect on the dynamic response of rock specimens.
88 citations
TL;DR: In this article, the authors investigated the long-term performance, mechanical properties, and durability of a mortar comprising ceramic waste as supplementary cementitious material and ceramic particles as fine aggregates.
85 citations
TL;DR: In this article, the rheological properties of different recycled powders (RPs) processed from the construction and demolition wastes, which were clay brick powder, mixed brick powder (MBP) and dust powder (DP), were investigated for better understanding the effect on the properties of mortar.
82 citations
TL;DR: In this article, the energy consumption of aerated concrete blocks and sintered clay bricks was investigated. And the results showed that aerated blocks are easier to crush than sinted clay bricks, but the energy cost of grinding aeratedcrete blocks into powder finer than 0.30mm is higher than that of grinding sintering clay brick powder.
TL;DR: In this article, the authors employed the recycled sand into the mix of 3D printed mortar and explored the green strength development at early ages within 2.5h after extrusion, where 25% and 50% natural sand was replaced by recycled sand which was crushed from waste concrete in the mix.
TL;DR: In this article, the authors reviewed the mechanical and durability properties of mortar and concrete using waste glass as partial replacements of cement and natural sand and found that the properties of glass powder blended cement mortar or concrete are mainly dependent on several factors such as particle size, replacement level, colour and type of the glass and curing age and curing temperature.
Abstract: Safe disposal of the huge amount of waste glass has become a serious environmental concern in many countries. On the other hand, production of concrete uses huge amount of natural resources and adds greenhouse gases to the environment. Therefore, researchers have been working on the reuse of waste glass as a supplementary cementitious material (SCM) and aggregate in the production of cement mortar and concrete. This paper reviews the mechanical and durability properties of mortar and concrete using waste glass as partial replacements of cement and natural sand. The optimum proportions of waste glass as in cement based construction materials in different ways have been identified and critically discussed by the analysis of experimental data available in various published literatures. It was found that the properties of glass powder blended cement mortar or concrete are mainly dependent on several factors such as particle size, replacement level, colour and type of the glass and curing age and curing temperature. The use of glass powder significantly improved the mechanical and durability properties of cement mortar and concrete when the particle size of glass powder is less than 45 μm and cement replacement rate is about 10–40%. It was also observed that glass fine aggregate can be used as up to 100% of the fine aggregate in mortar and concrete without negative effects on mechanical and durability properties when the particle size is less than 1 mm. The combined use of glass as SCM and fine aggregate reduced the mechanical properties of cementitious systems ; however, improved some durability properties. Moreover, the current research progress on waste glass mixed cementitious systems is critically reviewed and some future research is recommended.
TL;DR: This dataset describes the compressive strength and ultrasonic pulse velocity of mortar consisted of high content of GGBS and CKD combinations as a partial substitute for cement at the ages of 1, 2, 3, 7, 14, 21, 28, 56, 90 and 550 days, which can help the researchers to understand the behaviour of GG BS and CKd in high replacement levels for cement during early and later ages.
TL;DR: A printing system including supporting subsystem, controlling subsystem, feeding subsystem, and extruding subsystem was developed by considering the properties of mortar and the large-size characteristics of 3D mortar printing (3DMP), and it is shown that replacing natural sand with 25% of recycled sand caused higher green strength and no obvious decrease in hardened mechanical properties.
Abstract: 3D concrete printing (3DCP) has received worldwide attention in recent years. However, very limited studies have been carried out on the simultaneous research and mutual coordination of printing system, process design and printing material. In this study, a printing system including supporting subsystem, controlling subsystem, feeding subsystem, and extruding subsystem was developed by considering the properties of mortar and the large-size characteristics of 3D mortar printing (3DMP). The process design of 3DMP, such as tool path and printing parameters, was also redesigned to improve the printing qualities. The properties of printing mortars with/without recycled sand were then comparatively studied, followed by a successful on-site printing of a 2.5 m × 2.5 m × 3 m room. Results have shown that replacing natural sand with 25% of recycled sand caused higher green strength and no obvious decrease in hardened mechanical properties. By properly adjusting printing parameters, the printing mortars (with or without recycled sand) can be well-matched with the printing system. This verifies the practicability of the developed printing system as well as the method of partial application of recycled sand in 3DMP. Besides, it is recommended that both real-time monitoring system and continuous printing are necessary to achieve higher printing quality and efficiency.
TL;DR: In this article, the effects of different types of nanoparticles, namely nano-SiO2 (NS), nano-TiO2(NT), and nano-Fe2O3 (NF), on the fresh properties, mechanical properties, and microstructure of cement mortar containing fly ash as a supplementary cementitious material were explored.
TL;DR: In this paper, basalt fiber and nano-silica were used to reinforce recycled concrete to enhance the elevated temperature performance of the recycled concrete and expand its application space, and the results indicated that basalt fibre and nano silica contribute to the improvement of the interface transition zone performance and to the elevated temperatures.
TL;DR: In this article, thermogravimetric, energy dispersive X-ray, differential thermal, and powder Xray diffraction analyses were performed on a set of commercially available reactive MgO and fine recycled concrete aggregates.
Abstract: In this paper, mortar specimens were produced using two types of commercially-available reactive MgO as partial cement replacement (10%, 15% and 20%, by weight) and fine recycled concrete aggregate as siliceous sand substitute (50% and 100%, by volume). The specimens were subjected to thermogravimetric, energy dispersive X-ray, differential thermal and powder X-ray diffraction analyses. The mechanical and durability performance of all specimens was evaluated in terms of their flexural and compressive strength, dynamic modulus of elasticity, water absorption by capillary action, carbonation, and shrinkage. The main results indicate an overall decline in mechanical and durability-related performance with the use of both MgO and fine recycled concrete aggregates, but enhanced shrinkage behaviour was observed in all MgO-containing specimens.
TL;DR: In this paper, the authors investigated the properties of fly ash and GGBFS blended mortar using waste glass cullet and found that the replacement of natural sand by using various percentages of waste glass aggregate in alkali-activated mortar offers comparable properties to those using natural sand.
TL;DR: In this article, the effect of paper sludge ash (PSA) waste on the surface electrical resistivity and compressive strength of mortar was investigated in three grinding periods (in addition to without grinding), two replacement levels and three testing ages were considered.
Abstract: Cement is considered a base material in preparing blending mixtures that applying in various projects in the civil engineering field. Nevertheless, the cement production process cause indubitable negative environmental influences such as emitting CO2. The production of cement produces around 7% of the global CO2 emissions. Thus, searching for alternate binders in building processes to minimise or substitute cement has been one of the social problems. A by-product or waste products are among the potential alternatives to the mentioned problem. The present investigation involves the consumption of paper sludge ash (PSA) waste as cement replacement to produce environmentally friendly, cementitious material. Limited studies were addressed the PSA grinding time impact on mortar or concrete properties. Moreover, limited studies replaced the cement with high volume of PSA. Therefore, during this study, the effect of grinding time and replacement level (up to 50%) of the PSA on the surface electrical resistivity and compressive strength of mortar were investigated. Three grinding periods (in addition to without grinding), two replacement levels and three testing ages were considered. The results indicated that grinding the PSA for 10 minutes and use it to replace up to 50% of the cement content have similar mechanical and durability performance to ordinary Portland cement after 28 curing days. This innovative binder will also cause a major difference in decreasing the building materials cost and CO2 emissions.
TL;DR: In this article, the influence of exposure temperature and resolution of X-ray CT on the determination of microstructure parameters of heat-treated mortar was focused, and it was found the porosity and pore size increased slightly when the exposure temperature varied from 105°C to 200°C and significant pore coarsening and micro-damage occurred once the temperature exceeded 400°C.
TL;DR: In this paper, a methodology of partial replacement of the sand, commonly used for mortar production, by ornamental stone-processing waste was proposed, which not only justifies the replacement but also improves the technological properties of the mortar as a cementitious composite material.
TL;DR: In this article, an aqueous epoxy resin with four different dosages was employed to enhance ordinary Portland cement (OPC) mortar for the first time used as a polymer-cement repairing material.
TL;DR: In this article, the authors investigated the resistance of fly ash (FA) based 3-day and 28-day old geopolymer mortars to both HFs and high thermal cycles simultaneously and separately.
TL;DR: In this article, the use of construction and demolition waste (CDW) as a replacement of natural sand in coating mortars was evaluated and the results demonstrate that the substitution of more than 25% CDW for sand requires relatively larger amounts of water in the mortar.
Abstract: Several countries in the world have experienced considerable economic growth in the construction sector in recent decades, culminating in the demolition and reconstruction of large structures of reinforced concrete, that produced large amounts of solid waste. Much of this construction and demolition waste (CDW) is deposited in landfills, which generates high costs. The objective of this work is to evaluate the use of CDW as a replacement of natural sand in coating mortars. Four mortar mixtures, 1:1:6 (cement:lime:natural sand), with partial and total substitutions of the natural sand were investigated for CDW addition of 0 (reference), 25, 50 and 100 wt.%. Physical characterization of the CDW was carried out by particle size analysis while chemical composition was disclosed by EDX. Technological properties related to mortar fluidity, mechanical strength, mass density and water absorption by capillarity as well as environmental characteristics associated with leaching and solubilization of mortars, were evaluated. In addition, the compactness of the material was verified through Rene Feret's law. The results demonstrate that the substitution of more than 25% CDW for sand requires relatively larger amounts of water in the mortar. With regard to the degree compactness, the use of CDW improves the degree of compaction of the evaluated mortars and increase the compressive strength. However, the water absorption of the mortar increased with the levels of incorporated CDW. Therefore, to attend standard requirements for mortars, it is not possible to use CDW contents above 25%.
TL;DR: In this paper, the impact of slag content, activator dosage, retarder content and curing temperature was evaluated on fresh and early-age mechanical properties of one-part fly ash/slag-based alkali activated mortar.
TL;DR: In this paper, the effect of pre-treatment of crumb rubber aggregates with sodium hydroxide (NaOH) solution for 1h and 24h on workability, compressive strength, flexural strength, water absorption, thermal conductivity, and microstructural properties of mortar mixes was investigated.
TL;DR: In this article, the effects of glass powder (GP) as a partial precursor on properties of both OPC and alkali-activated slag (AAS) mortars were evaluated.
TL;DR: In this article, the authors compared the properties of different SiO2/Na2O activators with different modulus values and compared the results with one-part (or dry-mix) alkali-activated blast furnace slag mortar.
TL;DR: It was determined that by increasing the recycled glass sand aggregate content, the density of mortar decreased and the relationships between the properties for mortar containingGlass sand aggregate, and the modulus of elasticity and Poisson coefficient.
Abstract: A responsible approach towards sustainable development requires the use of environmentally friendly, low-carbon, and energy-intensive materials. One positive way is to use glass waste as a replacement for fine natural aggregate. For this purpose, the effects of adding glass cullet to the mechanical properties of mortar were carried out. The glass aggregate made from recycled post-consumer waste glass (food, medicine, and cosmetics packaging, including mostly bottles), were used. This experimental work included four different contents of fine glass cullet (5, 10, 15, and 20 wt.% of fine aggregate). The compressive, flexural, and split tensile strengths were evaluated. Moreover, the modulus of elasticity and Poisson coefficient were determined. The addition of glass sand aggregate increases the mechanical properties of mortar. When comparing the strength, the obtained improvement in split tensile strength was the least affected. The obtained effect for the increased analysed properties of the glass sand aggregate content has been rarely reported. Moreover, it was determined that by increasing the recycled glass sand aggregate content, the density of mortar decreased. In addition, the relationships between the properties for mortar containing glass sand aggregate were observed.