scholarly journals Effect of Pre-Wetting Recycled Mortar Aggregate on the Mechanical Properties of Masonry Mortar

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1547
Author(s):  
René Sebastián Mora-Ortiz ◽  
Ebelia Del Angel-Meraz ◽  
Sergio Alberto Díaz ◽  
Francisco Magaña-Hernández ◽  
Emmanuel Munguía-Balvanera ◽  
...  

In this research we evaluated the use of recycled fine mortar aggregate (RFMA) as a fine aggregate for new masonry mortar creation. The pre-wetting effect on the aggregate before creating the mixture was analyzed as a method to reduce its absorption potential. A control mixture of conventional mortar and two groups of recycled mortars were designed with a partial replacement of natural sand by RFMA (pre-wetted and not pre-wetted) performed in different proportions. The results established that the pre-wetting process allows a reduction in the amount of water required during the creation of new mixtures, regulating the water/cement (W/C) ratio and improving the properties of recycled mortars such as air content, fresh and hardened densities, and compressive and adhesive strength for all substitution levels. Mortar made with a 20% substitution and pre-wetted until it was at 67% of its absorption capacity displayed adhesive values higher than the ones shown by the reference mortar. The pre-wetting process proves to be an easy performance technique; it is inexpensive, environmentally friendly, and the most valuable fact is that specialized equipment is not necessarily needed. This process is the most profitable option for improving RFMA exploitation and reuse.

2018 ◽  
Vol 760 ◽  
pp. 204-209 ◽  
Author(s):  
Magdaléna Šefflová

This study deals with determination of the properties of the fine recycled aggregate (FRA) concrete with partial replacement of natural sand in concrete mixtures. The FRA was obtained from concrete waste and crushed on fraction 0 – 4 mm by laboratory jaw crusher. The geometrical and physical properties of natural sand and the FRA were tested. The main goal of this study is evaluation of the basic physical and mechanical properties of the concrete with partial natural sand replacement by the FRA such as workability, water absorption capacity, compressive strength and flexural strength. A total four concrete mixtures were prepared. The first concrete mixture was prepared only with natural sand, did not include the FRA. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios (40 %, 50 %, and 60 %). All concrete mixtures were designated with the same parameters for clear comparison. The workability of fresh concrete mixtures and physical and mechanical properties of hardened concrete were tested.


2018 ◽  
Vol 760 ◽  
pp. 193-198 ◽  
Author(s):  
Kristina Fořtová ◽  
Tereza Pavlů

This paper presents research results of recycled fine aggregate concrete testing. The main aim of this contribution is verification of properties of fine aggregate concrete with partial replacement of fine natural aggregate by recycled masonry aggregate originated from construction and demolition waste. The influence of partial replacement of natural sand to mechanical properties and freeze-thaw resistance is described. The compressive strength and flexural strength were tested at the age of 28 and 60 days and after 25, 50, 75 and 100 freeze-thaw cycles. Partial replacement of natural sand was 0, 25 and 50 % for all these tests. Prismatic specimens were examined.


2011 ◽  
Vol 243-249 ◽  
pp. 5775-5778 ◽  
Author(s):  
M. Devi ◽  
K. Kannan

Demand for natural sand in concrete is increasing day by day since the available sand cannot meet the rising demand of construction sector. This paper reports the experimental study undertaken to investigate the influence of partial replacement of cement with Ground Granulated Blast Furnace Slag(GGBFS) in concrete containing quarry dust as fine aggregate. The cement was replaced by 10%, 20%, 30%, 40% and 50% of GGBFS and tests were conducted to determine the optimum level of replacement of GGBFS in quarry dust concrete. The specimens were subjected to compressive strength, split tensile strength, flexural strength, and bond strength tests at 7days, 28days, 56days, 90days and 150 days. The resistance to corrosion is evaluated based on the performance of the concrete for the penetration of chloride ions by means of impressed voltage technique in saline medium and Gravimetric weight loss method. Results herein reveal that an increase in slag proportion increases the strength properties and decreases the rate and amount of corrosion of reinforcement and among the various percentages of replacement 40% is found to be optimum with better strength and corrosion resistance properties.


Concrete is a material which widely used in construction industry. The present investigation deals with the study of partial replacement of fine aggregate by Nylon Glass Granules in concrete. The fine aggregates are replaced by 0%, 10%, 20% and 30% by Nylon Glass Granules by volume of natural sand in M35 grade of concrete. Additionally, to increase the tensile strength of concrete 1% of Steel Fiber by volume of cement were added to all the mixes containing Nylon Glass Granules. The concrete produced by such ingredients were cured for 7 and 28 days to evaluate its hardened properties. The 28days hardened properties of concrete revealed that maximum strength is observed for the mix which possesses 20% replacement of fine aggregate by Nylon Glass Granules compared with the conventional concrete, thus it is said to be the optimum mix


Author(s):  
Wojciech Kubissa ◽  
Roman Jaskulski

In the article the possibility of using surface blast-cleaning waste (copper slag based) as a replacement of fine aggregate in high performance concrete manufacturing was presented. Concrete with w/c ratio 0.45 and 360 kg/m3 dosage of cements: CEM I 42.5R, CEM II/B-V 42.5N and CEM III/A 42.5N was tested. The consistency measured in table flow test was assumed as 420 ± 30 mm so superplasticizer was used. The replacement rate of the fine aggregate 0–2 mm with the copper slag (CS) waste was 66 %. Concrete mixtures with sand served as reference. The performed tests focused on: compressive and tensile strength (both after 28 days), sorptivity, free water absorption capacity, Torrent air permeability, and chloride ingress depth after salt fog treatment. A freeze resistance test was also carried out according to PN-B-06265. The obtained results showed that the strength and some other tested properties of concrete mixtures with copper slag waste were similar or better than those of the mixtures with sand. The results of the tests indicate that the concrete with copper slag waste is more tight than the concrete with sand and therefore is more durable.


2021 ◽  
Vol 1203 (2) ◽  
pp. 022115
Author(s):  
Luis G. Baltazar

Abstract The construction sector is one of the largest and most active in the world economy, being responsible for consumption of huge amounts of natural resources. Natural sand and gravel are the most important resources in construction, they are mainly used as aggregates, and its extraction often causes environmental damages. Bearing these considerations in mind, the wood waste has been used as partial replacement of natural sand in concrete and mortars to reduce the environmental burden of natural sand extraction. The aim of this paper is to characterize the physical and mechanical properties of natural hydraulic lime-based mortars proportioned with different percentages of wood wastes (0% to 30%) as replacement of natural sand. Thus, several specimens of mortar proportioned with wood wastes have been subjected to different experimental procedures, such as: workability, mechanical strength, water absorption and thermal conductivity. Results obtained showed that the incorporation of wood waste causes a reduction of mechanical resistance mostly due to the increase in open porosity, but on the other hand the thermal conductivity presents an improvement up to 83%. The results obtained are quite acceptable and encouraging for the follow-up studies using wood wastes as fine aggregate in mortars and, simultaneously, to improve the energy efficiency of buildings since this waste material contributes to obtain mortars with improved thermal performance.


Author(s):  
Magdalena Dobiszewska ◽  
Krzysztof Wrzecion

Concrete production consumes much energy and large amounts of natural resources. It causes environmental, energy and economic losses. Cement industry contributes to production for about 7% of all CO2 generated in the world. Every ton of cement production releases nearly one ton of CO2 to atmosphere. Thus the concrete and cement industry changes the environment appearance and affects it to a great extent. On the other hand, there is an increase in demand and decrease in natural sources of concrete constituents, like sand. The use of rock dust as the replacement for natural sand will solve the problem of dust disposal. The present study shows the results of the research concerning the modi-fication of concrete with waste dust. It is the waste from the preparation of aggregate used in asphalt mixture production. Concrete modification consists in that the powder waste is added to concrete as partial replacement of fine aggregate. Previous studies have shown that analysed waste has a beneficial effect on compressive strength, flexural strength as well as freeze resistance. The use of mineral powder as the partial substitution of fine aggregate allows for the effective management of industrial waste and improves some properties of concrete.


2019 ◽  
Vol 1 (6) ◽  
pp. 537-542
Author(s):  
Anukarthuika B ◽  
Priyanka S ◽  
Preethika K

Concrete plays important role in the construction of structures. The need for concrete increases day by day. Material required for concrete are getting depleted, so there is a requirement to find alternatives. At the same time the alternative materials should posses the property of the actual materials used in concrete and also they must provide the required strength to the concrete. Normally Concrete is firm in compression but anemic in tension and shear. The purpose of this study is to find the behaviour of concrete reinforced with hybrid macro fibers. By adding Glass fibers in percentages like 0.2%, 0.4%, 0.6%& 0.8% to the concrete, the properties like compressive, flexural and split tensile strength are investigated. The optimum percentage of glass fiber was found to be 0.4%. Quarry dust has been widely used in structures since ancient times. The present study is aimed at utilizing waste Quarry dust (WQD) in construction industry itself as fine aggregate in concrete, replacing natural sand and also by adding the optimum percentage of glass fibers. The replacement is done partially and fully in the various proportions like 0%, 25%, 50%, 75% and 100% and its effect on properties of concrete were investigated. The optimum percentage of the concrete by adding 0.4% of glass fiber and the proportions was found to be 25%.


2016 ◽  
Vol 825 ◽  
pp. 45-48 ◽  
Author(s):  
Tereza Pavlů ◽  
Magdaléna Šefflová

This study deals with determination of the physical properties of fine-aggregate concrete with partial replacement of cement in concrete mixture. Cement was replaced by recycled cement powder originating from construction and demolition waste. The main goal of this study is evaluation of the basic physical properties of the fine-aggregate concrete with partial cement replacement by recycled concrete powder such as density, water absorption capacity and capillary water absorption. The fine recycled concrete which was used as partial replacement of cement had the same grain size as cement. The replacement rate was 0 %, 5 %, 10 % and 15 %. Physical properties were investigated by using cubic and prismatic specimens.


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