Seashells and Oyster Shells: Biobased Fine Aggregates in Concrete Mixtures

Author(s):  
Giuliana Scuderi

The construction industry is the largest global consumer of materials, among which sand plays a fundamental role; now the second most used natural resource behind water, sand is the primary component in concrete. However, natural sand production is a slow process and sand is now consumed at a faster pace than it’s replenished. One way to reduce consumption of sand is to use alternative materials in the concrete industry. This paper reports the exploratory study on the suitability of aquaculture byproducts as fine aggregates in concrete mixtures. Seashell grit, seashell flour and oyster flour were used as sand replacements in concrete mixtures (10%, 30% and 50% substitution rates). All the mixtures were characterized in fresh and hardened states (workability, air content, compressive strength and water absorption). Based on compressive strength, measured at 7 and 28 days, seashell grit provided the most promising results: the compressive strength was found to be larger than for conventional concrete. Moreover, the compressive strength of the cubes was larger, when larger percentages of seashell grit were used, with the highest value obtained for 50% substitution. However, for oyster flour and seashell flour, only 10% sand substitution provided results comparable with the control mixture. For the three aggregates, workability of concrete decreases with fineness modulus decrease. For mixtures in which shell and oyster flour were used with 30% and 50% substitution percentages, it was necessary to increase the quantity of mixing water to allow a minimal workability. In conclusion, considering the promising results of the seashell grit, it is suggested to study further the characteristic of the material, also considering its environmental and physical properties, including acoustic and thermal performances. Higher substitution percentages should also be investigated. This research adds to the relevant literature in matter of biobased concrete, aiming at finding new biobased sustainable alternatives in the concrete industry.

2012 ◽  
Vol 517 ◽  
pp. 547-555 ◽  
Author(s):  
Edgar Bacarji ◽  
V.C. Marques ◽  
Romildo Dias Toledo Filho

Environmental preservation has been a theme debated in virtually every country in the world. Many measures are being taken to reduce the environmental impact due to unplanned development. Growing environmental restrictions to the exploitation of sand from riverbeds have resulted in a search for alternative materials to produce fine aggregates, particularly near to larger metropolitan areas. Artificial fine aggregates then appear as an attractive alternative to natural fine aggregates for concrete. This work is the final part of a study about the use of residues in concretes. Conventional Concrete (CC) and Self-compacting concrete (SCC) were developed replacing the natural sand by two types of mineral waste. Fresh state tests such as slump-flow, L-box, V-funnel test and column test were performed according to the Brazilian standards. The rheological characteristics (yield stress and plastic viscosity) of the SCC were determined using the BTRHEOM rheometer. At the hardened state, compressive strength was determined at 3, 14 and 28 days of age. Modulus of elasticity test was carried out at 28 days. Curves to mixture design were obtained to SCC and CC. For all mixtures and properties analyzed the good performance of the mineral waste used was proven. Finally and more important, it was demonstrated that it is possible to obtain structural self-compacting concrete, self-compacting concrete without structural purposes and conventional concrete by using mineral waste that works like fine aggregates and that on the other hand, without any destination, would cause serious environmental impacts.


2021 ◽  
Vol 1019 ◽  
pp. 82-91
Author(s):  
I. Rohini ◽  
R. Padmapriya

Copper slag can be considered as waste product which could have a favorable future in construction industry as a substitution to fine aggregates in concrete. Concrete is a very brittle material and in due course of time it tends to crack .These cracks, expands and corrodes the steel reinforcement which intensify the cost of maintenance and decreases the structural stability over periods of time. To avoid crack formation in concrete microorganism can be directly added to concrete during the mixing stage which is called as bacteria impregnated concrete. Bio concrete makes use of calcium carbonate precipitation in the presence of the suitable media results in microbial induced calcite crystals. This work reports an experimental procedure to investigate the effect of using copper slag in concrete when it is remedied by microorganism. Five series of concrete mixtures were prepared with different proportions of copper slag ranging from 0%, 25%, 50%, 75% and 100% to fine aggregate. Copper slag concrete mixtures were treated with 1% and 2% microorganisms by the weight of cement. All Specimens were cured for 7, 14 and 28 days before testing. Mechanical properties such as Compressive strength and Flexural Strength of Bacterial copper slag concrete were found and compared with the conventional concrete. The highest Compressive strength obtained was 45.6 Mpa at 75% substitution of copper slag with 2% microorganism and the corresponding strength for control mix was 26.8Mpa. The highest flexural strength obtained was 10.3Mpa and the corresponding strength for control mix was 4.5Mpa.It has been observed that 75% replacement of copper slag can be effectively used as a replacement for fine aggregate when it is treated by Microorganisms.


2017 ◽  
Vol 1144 ◽  
pp. 59-64 ◽  
Author(s):  
Magdaléna Šefflová ◽  
Tereza Pavlů

This paper is focused on the durability of recycled aggregate (FRA) concrete. The durability of FRA concrete is connected with many uncertainties and doubts. This paper presents results of long-term of compressive strength, freeze – thaw resistance and carbonation depth of FRA concrete. The FRA was originated from crushed old concrete structures. There were prepared a total four concrete mixture. The first mixture was reference with natural sand. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios, specifically 10 %, 20 % and 30 %. All prepared concrete mixtures were designated with the same parameters for clear comparison. It is possible to say that according to the durability, the FRA concrete is possible to used in the same applications as conventional concrete. However it is necessary to verify this results.


2021 ◽  
Vol 1 (1) ◽  
pp. 1-14
Author(s):  
Nurul Noraziemah Mohd Pauzi

The issue of the cathode ray tube (CRT) technology facing its end-of-time and increasing quantities across the globe has acquired the responsiveness of many researchers. The use of waste CRT glass as a construction material has fascinated them due to its significant advantage in recycling the hazardous and non-biodegradable waste CRT glass. However, lack of knowledge about the effects and features of CRT glass as a construction material could be a hindrance to the excessive utilization of waste CRT glass. Therefore, in order to establish the idea of using CRT waste glass as a more common construction material, this paper reviews several recycling techniques of CRT glass and further detail on the workability, density, and compressive strength properties of concrete and mortar using CRT glass (treated or untreated) as fine aggregates. The review showed that, generally, the use of CRT glass as a complete or partial replacement of natural sand shows a slight increase in density, workability, and concrete strength compared to conventional concrete. However, there are no clear trends that can be concluded as this review also showed that various factors influenced its performance, such as percentage replacement, particle size, lead (Pb) content, and types of admixtures.


Author(s):  
Chun-Yi Kuo ◽  
Reed B. Freeman

The performance of asphalt concrete mixtures is influenced by the properties of the included aggregates, such as grading, shape (angularity and elongation), and texture (roughness). Complete and accurate quantification of aggregate properties is essential for understanding their influence on asphalt concrete and for selecting aggregates to produce high-quality paving mixtures. Recent developments in the use of digital image analysis techniques for quantifying aggregate morphological characteristics in asphalt concrete are summarized. Image morphological characteristics were used to quantify flatness and elongation of coarse aggregates, to estimate the proportion of natural sand in fine aggregates, and to correlate aggregate characteristics with engineering properties of asphalt concrete mixtures. Image analysis of sections also revealed information about the grading, shape, and orientation of coarse aggregates in a mixture. An overview is presented of the broad range of useful pavement engineering applications of this relatively new approach for evaluating aggregate characteristics.


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


2019 ◽  
Vol 23 (3) ◽  
pp. 70-84 ◽  
Author(s):  
Zinta Zimele ◽  
Maris Sinka ◽  
Aleksandrs Korjakins ◽  
Diana Bajare ◽  
Genadijs Sahmenko

Abstract Global warming being increasingly discussed, solutions for reducing emission greenhouse gases become more important in all industry sectors. The total energy consumed in the construction sector contribute up to 1/3 from all greenhouse gases emissions. Large part of it comes from the cement production – 5 % of the total global emissions. The foam concrete is lightweight concrete with good thermal properties and ability to reduce CO2 emissions by reducing the use of cement due to its low density. The aim of this study is to determine impact on the environment with the use of Life Cycle Assessment (LCA) with focus on Global Warming Potential (GWP) for two different compressive strength foam concrete mixtures produced in Latvia by unique intensive mixing technology – turbulence with cavitation effect. Afterwards, the selected foam concrete mixtures are compared with alternative materials with similar compressive strength – aerated concrete and hollow ceramic blocks. The foam concrete mixture having 12.5 MPa compressive strength showed higher CO2 emissions than hallow ceramic block. The majority of CO2 emissions comes from the Portland cement, which is a key element in its composition. On the other hand, the foam concrete mixture having 2.4 MPa compressive strength showed higher CO2 emissions than aerated concrete block. The majority of CO2 emissions are due to foam glass granules, which is the main element contributing to the increased insulation properties of the material. Comparison of each foam concrete with analogue building material by compressive strength shows that the chosen foam concrete mixtures produce greater GWP than alternative materials. This research allows to identify the environmental impacts of different foam concrete mixture components and to improve these mixtures to achieve similar properties with less impact, for example, by replacing foam glass granules with granules made from recycled glass or replacing cement with flay ash, silica fume or recycled glass powder.


Author(s):  
Ben Ngene ◽  
Gideon Bamigboye ◽  
Osato Asemota

Weight and Environmental concerns are two elements that have made the search for alternative materials of construction critical in today’s construction industry. The importance of finding a solution to the problem has given rise to the use of non-degradable materials. This study examines the challenges of making such material as polystyrene used in product packaging a part of the structural element in construction. Such adventure it is envisaged reduced the volume and number of landfill sites in Nigeria where air pollution arising from dump sites affects the health of citizens. To achieve this aim, Styrofoam was used as a partial replacement for coarse aggregate (granite) by volume. The replacement was carried out in varying percentages of 10, 20 and 30% Styrofoam concretes respectively with a concrete mix ratio of 1:1:2. The result obtained showed that concrete produced using Styrofoam as the alternative aggregate possess lesser values of compressive strength when compared with the control of conventional concrete without Styrofoam. The optimal percentage of a replacement for Styrofoam concrete was 10% with a compressive strength of 21.33 N/mm2 while the control concrete had a compressive strength of 33.26 N/mm2. The loss of strength of Styrofoam concrete is compensated by the reduction of the requirement for landfill sites and the attendant pollution generated while the concrete can be used for non-structural elements in construction.


2021 ◽  
Vol 2 (1) ◽  
pp. 26-34
Author(s):  
Tek Raj Gyawali

Roller compacted concrete (RCC) is the zero slump concrete produced from the same materials used in conventional concrete. The mortar used in RCC plays a significant role for the workability, strength and durability of the concrete. The air content in the mortar is the key factor for durability, especially to resist the freezing and thawing action. The main target is to produce the microscopic air cells inside the mortar using air-entrained agent and minimize the entrapped air as little as possible. Air content may range from 4~7% depending upon the type of concrete. The effect of the content of AE 303A type air-entrained agent was studied for the fresh and hardened properties of the RCC mortar. The result showed that it has an almost negligible effect on the workability of mortar, but highly effective for the density and compressive strength of hardened mortar. The use of 0.02% (by weight of cement) increased the air content about 4.5 times of the base mortar (without the use of the agent), from 2% to 9.1%. However, the density was decreased by about 10 % (from 2.18 gm/cm3 to 1.96 gm/cm3) and the 28 days compressive strength by about 49% (from 21.90 MPa to 14.73 MPa). The model, developed for the mortar of the dam concrete, has also been well satisfied with the experimental results for the case of RCC mortar.


2020 ◽  
Vol 6 (4) ◽  
pp. 462-471

Abstract: The composition of the concrete mixture determines the compressive strength. Concrete mixtures generally consist of cement, water, coarse aggregates, fine aggregates, and concrete drugs. In this study, it will be tried to mix stone ash and coconut fibers. The purpose of this study is to find out the concrete compressive strength with add stone ash and coconut fibers to normal concrete. Data was collected through laboratory tests by carrying out an additional mixture of stone ash and coconut fibers. There were six types of specimens produced which were measured for 7, 14, 21, and 28 days. Variation of specimens 1) normal concrete, 2) normal concrete + stone ash, 3) normal concrete + coconut fiber (1.5%), 4) normal concrete + stone ash and coconut fiber (1.5%), 5) normal concrete + stone ash and 1% coconut fiber, 6) normal concrete + 1% coconut fiber. From the results of testing the concrete compressive strength was obtained 455 kg/cm2 for the age of concrete for 28 days with a mixture of normal concrete + stone ash.


Sign in / Sign up

Export Citation Format

Share Document