Experimentation of Durable Concretes, Produced by Traditional Aggregates, in Marine Environment (original) (raw)
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Production of Durable Concrete with River Material of Albania, Used in a Marine Environment
2014
This paper presents an analysis of a normal environment concrete of 45 MPa (NC 35/45) and marine durable concrete of 45 MPa (MC 35/45) compressive strength and permeability of durable concrete. Both the types of concrete were produced with river materials with different chemical composition. After 90 days were measured the penetration of chloride and water penetration in specimens of durable concrete that are treatment in two environmental conditions
2014 UBT International Conference, 2014
This article describes the effect of durable concrete in two different environments, which is produced by traditional mountain aggregates. For this purpose, we have produced concrete of class C30/37 with aggregates from mountain quarry. Meanwhile, we have not changed other components of concrete. Watercement report is 0.4-0.61. During experimental faze, are done comparisons of resistance to compression, water and chlorides penetration for specimens of concrete which are curing in normal environment (N) and in marine environment (A). Concrete cubes produced, were treated in marine and normal environment for 3, 7 and 28 days in Durres coastal city, Albania. Finally, results are compared to each other and conclusions are made on this basis.
Marine Durability of 30-Year Old Concrete Made with Different Cements
Journal of Advanced Concrete Technology, 2003
Marine durability of 30-year-old concrete specimens made with ordinary portland cement (OPC), high early strength portland cement (HES), moderate heat portland cement (MH), slag cement of type B (SCB), and alumina cement (AL) was investigated. Other parameters include sulfate content in cement, mixing water, and different exposure zones. Compressive strength, chloride ingress, corrosion of steel bars in concrete, microstructure, mineralogy of concrete, and steel-matrix and aggregate-matrix interfaces were investigated. Chloride ingress in concrete was sequenced as OPC, HES, MH>SCB>AL. However, for AL mixed with tap water, corrosion on steel bars in concrete was higher. For SCB and AL, the pore volume at the outer region of the specimens is reduced due to the ingress of chloride and other ions from seawater.
Every year a lot of newer structure is rising and making the land for construction smaller day by day which leads the construction heading towards the coastal areas. But seawater intrusion in coastal regions has a great impact on the strength of concrete structures. Again recycled aggregates of demolished concrete are being wasted without any beneficial use. These recycled aggregate can be reused in concrete construction in the coastal regions if it is possible to gain a rational percentage of strength after some specified curing periods.So to study the optimum percentage of recycled aggregate on recycled concrete in marine environment, three types of variables are used in this study. Percentage of recycled aggregate, curing period and concentration of saline water are those three variables involved. For this study 3 various percentage of recycled aggregate used in concrete casting which are 30%, 40% and 50% recycled aggregate. For the 3 different types of aggregate samples 3 different types of concrete has been cast in 100 mm cube specimen and cured in 3 different concentrations of 1N, 3N and 5N curing water. The specimens are then tested for compressive strength for curing periods of 28 days, 60 days and 90 days. The results of compressive strength test of these recycled concrete are then compared with the compressive strength of plain concrete with 0% recycled aggregate cured in plain water by considering it as a standard. From the investigation work it has been found that concrete cast with 30% recycled aggregate achieves 95.4% compressive strength for 28 days curing in 1N concentration of saline water, which is comparatively higher among other recycled concrete used here. Percentage of strength achievement are higher for 28 days curing but it starts to decrease with the increase of curing period in saline water compared to the strength of concrete cured in plain water. Compressive strength decreases with increasing percentage of recycled aggregate and increasing concentration of salinity. Thus 30% is the optimum percentage of recycled aggregate which is accessible to use in marine structures only when curing in high saline water can be avoided as much as possible.
A Review on Strength of Concrete in Seawater
International Journal of Engineering Research and, 2015
Several billion tons of water is annually used as mixing, curing and cleaning around the world, in concrete industry. As there is a scarcity of fresh drinkable water around the world; so there is a need to save fresh water and hence possibilities of using seawater as mixing as well as curing water should be investigated seriously. Additionally, if use of seawater as concrete material is permitted, it will be very convenient and economical in the construction; especially in the coastal works. However; most of the reinforced concrete codes do not permit the use of seawater due to risk of early corrosion of reinforcement. The effect of seawater on concrete deserves special attention as the coastal and offshore structures are exposed to simultaneous action of a number of physical and chemical deterioration processes. Moreover, 80 percent of the earth is covered by seawater either directly or indirectly (e.g. winds can carry sea water spray up to a few miles in land from the coast). Concrete piers, decks, breakwater , and retaining walls are widely used in the construction of harbors and docks. The use of concrete offshore drilling platforms and oil storage tanks is already on the increase. This paper illustrates the various research and their results that were carried out earlier on the experimental studies on the strength of concrete in seawater.
Technium Social Sciences Journal
With the increase of solid construction waste (CSW) due to the acceleration of urbanization in Algeria, many ecological and environmental issues have been raised. Recycling and reuse of construction waste helps to reduce pollution, carbon emissions and preserve resources. Few studies have focused on the durability characteristics of concretes based on fine aggregates recycled from brick and concrete waste. The main purpose of this study is to formulate and analyze the performance of HPC based on waste brick and concrete fines. The substitution of alluvial sand with brick fines, causes the reduction of the heat of hydration and delays the appearance of the thermal flux peaks. while HPC rich in crushed concrete waste increases the heat of hydration. The appearance of heat flux peaks coincides for all mixtures with fines of waste concrete substitution and they will be delayed and prolonged for HPC with sand based on waste brick.
EXPERIMENTAL STUDY OF INFLUENCE OF SEAWATER ON STRENGTH OF CONCRETE STRUCTURES
Against the background of direct and indirect action of physical and chemical deterioration of coastal and offshore infrastructures, the potential influence of seawater on the strength and durability of concrete structures were investigated. Cement concrete cubes of 150mm x 150mm x 150mm with cement, sand and aggregate mix ratio of 1:2:4 (mix-1) and 1:1.5:3 (mix-2) were prepared. A total number of 96 concrete cubes of different water cement ratio (w/c) of 0.4, 0.45 and 0.5 by weight were moulded. For the two mix ratios, casts in triplicate were cured in both freshwater (as control) and seawater for different periods of times (i.e. 14, 21, 28, and 90 days) followed by crushing-compressive strength tests. The study shows a proportionate increase in strength in the control casts from 17,286 to 23,673KN/m 2 and from 21,599 to 29,555KN/m 2 for mix-1 and mix-2 respectively as the curing time increased from 14 to 90 days. High compressive strengths observed for mix-2 casts compared to those of mix-1 casts was attributed to higher proportion of cement employed. In addition, the strength development for all cubes cured in seawater were relatively lower compared to those cured in freshwater at the end of the different testing periods until after 90 days; hence indications of possible negative impacts of salinity on the coastal concrete infrastructures and the need for protection measures.
IJERT-A Review on Strength of Concrete in Seawater
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/a-review-on-strength-of-concrete-in-seawater https://www.ijert.org/research/a-review-on-strength-of-concrete-in-seawater-IJERTV4IS030890.pdf Several billion tons of water is annually used as mixing, curing and cleaning around the world, in concrete industry. As there is a scarcity of fresh drinkable water around the world; so there is a need to save fresh water and hence possibilities of using seawater as mixing as well as curing water should be investigated seriously. Additionally, if use of seawater as concrete material is permitted, it will be very convenient and economical in the construction; especially in the coastal works. However; most of the reinforced concrete codes do not permit the use of seawater due to risk of early corrosion of reinforcement. The effect of seawater on concrete deserves special attention as the coastal and offshore structures are exposed to simultaneous action of a number of physical and chemical deterioration processes. Moreover, 80 percent of the earth is covered by seawater either directly or indirectly (e.g. winds can carry sea water spray up to a few miles in land from the coast). Concrete piers, decks, breakwater , and retaining walls are widely used in the construction of harbors and docks. The use of concrete offshore drilling platforms and oil storage tanks is already on the increase. This paper illustrates the various research and their results that were carried out earlier on the experimental studies on the strength of concrete in seawater.
Performance of blended cement concrete exposed to marine environment
Proceedings of the Second International Conference on Performance-based and Life-cycle Structural Engineering (PLSE 2015), 2015
Reinforced concrete exposed to the marine environment deteriorates more rapidly. Structures constructed at or near the sea shore have to be repaired more often than comparable structures located elsewhere. This study was carried out to develop an understanding of the performance of concrete made up of cements blended by pozzolanic materials. Several mix designs were formulated, incorporating the pozzolans like slag, fly ash and silica fume and calcium nitrate as the corrosion inhibitor. Mix designs were in accordance with ACI 211-1 and pozzolanic materials were added in accordance with ACI 233 and ACI 234. A number of tests were carried out during the study to compare the performance of samples cast from concrete of different mix designs. Tests conducted during the study were Rapid Migration Test (NT Build 492), Half Cell Potential (ASTM C 876), Absorptivity of the oven-dried samples (ASTM C 642), Compressive Strength Test (ASTM C 39) and Flexural Strength Test (ASTM C 293). Results showed that in almost all cases, use of cements blended with pozzolanic materials resulted in an enhanced performance of the concrete. Use of supplementary cementitious materials (SCM) in concrete provides a sustainable and feasible solution to the durability problems in coastal areas. Replacements of OPC by the pozzolan will not only help in conservation of natural resources, but it will also contribute towards reducing pollution and energy.
Experimental Analysis and Study of Sea Water and Sea Sand Concrete
International Journal for Research in Applied Science and Engineering Technology IJRASET, 2020
Concrete is one of the major construction material used in the construction now a day. It is a composite material containing cement, coarse aggregate, fine aggregate and water. In the future, fresh water will be very difficult to get and obtain. It is said that in 2024 half of the mankind will live in the areas where fresh water is not enough. Also, UN and WMO are predicting 5 billion people will be in short of even drinking water. The depletion of natural sand deposits and illegal sand mining is a common issue on these days. Extraction of river sand as fine aggregate affect negatively on river ecosystems, navigation and flood control. This paper presents an experimental critical review of existing studies based on the effects of using sea-sand and/or seawater as raw materials of concrete on the properties of the resulting concrete, short and long term strength as well as durability. It has been shown by some researchers that concrete made with sea water and sea sand develops its early strength faster than that of ordinary concrete, but the former achieves a long term strength similar. Attempts were made to over come the problems of using sea water and sea sand in concrete by adding some suitable material. The samples are from cochin, by the means of laboratory tests to assess the compatibility of modifying the samples. Compressive strength, flexural strength and tensile strength test was conducted on the various concrete specimens with various proportion for the comparison analysis. The effort of improving this technology saves fresh water and river, reduces water scarcity. I. INTRODUCTION In the year of 2016, the amount of cement produced in the world reached 4.20 billion tonnes and the estimated concrete production was around 25 billion tonnes. The production of aggregates (including both coarse and fine aggregate) reached about 40 billion tonnes in the year 2015. The consumption of huge amounts of raw materials, mainly river sand and freshwater, in concrete production has raised very serious environmental issues. The depletion of natural sand deposits and illegal sand mining is a common issue these days. Extraction of river sand as fine aggregate impacts negatively on river ecosystems, navigation and flood control. Similarly, the consumption of a great amount of freshwater poses a great challenge due to water shortage in many parts of the world. Besides sand and water, consumption of the other main constituents of concrete, has also caused major environmental concerns, but the present discussion is mainly concerned with alternative solutions for sand and water. The need of desalted sea sand and sea water cause to extra huge production cost. The direct use of both sea-sand and seawater without desalting in concrete production is particularly implemented for marine and coastal projects, for which the supplies of freshwater and river sand are limited where. Several studies agree that in comparison with concrete mixed with fresh water, concrete mixed with sea water increases early age strength and reduces setting time. The concrete produced with seawater using blast furnace slag cement and a low water cement ratio increases the resistance towards chloride penetration. Sea water can be used instead of fresh water where it is not available such as isolated islands and coastal areas. As a result, the topic of seawater sea sand concrete or sea sand seawater concrete has attracted the attention of us. The purpose of this project is to study about the use of sea-sand and seawater as raw materials for concrete to replace river sand and freshwater. In general, concrete cast with seawater but ordinary fine aggregate is referred to as seawater concrete, while concrete cast with sea-sand but freshwater is referred to as sea sand concrete. The demand for manufactured fine aggregates is increasing highly as river sand cannot meet the rising demand of construction sector. The limited supply capacity of natural sea sand cannot meet the supply guarantee needs. Under this circumstances the manufactured sand is impossible. In many countries sea sand has been used for making cement concrete since long time ago, naturally, its technology depends on the research achievement and specific conditions of each country. Therefore, studying the differences in properties of both river and sea sand will give an idea whether sea sand can be altered in such a way that it can be used as a substitute for the depleting river sand. Removing process of river sand from river bed has environmental impacts. The discussions presented in this report have clearly indicated that sea-sand and seawater structures are most attractive in marine/coastal construction, where steel corrosion is a major concern and access to river sand and freshwater is limited but sea-sand and huge amount of sea water are easily available, mainly in island and costal area where fresh water availability is low.