In vitro Bioactivity Assessment of Novel Composites Based on Calcium Aluminate Cement by Cortés-Hernández DA in Research & Development in Material Science
This document studies the suitability of using incinerated sewage sludge ash (ISSA) to produce geopolymer concrete as a partial replacement for fly ash. Key findings include:
1) XRF testing showed that ISSA has high concentrations of SiO2 and Al2O3 similar to fly ash, making it a potential candidate for geopolymer concrete.
2) Concrete made with only ISSA did not develop significant strength, but strength decreased gradually as ISSA percentage increased in mixes partially replacing fly ash up to 20%.
3) Concrete with up to 15% ISSA replacement was considered average quality and absorption, allowing potential use for less strength-critical applications.
4)
This document summarizes a study on the strength and shrinkage properties of alkali-activated slag concrete (AASC) placed in a large concrete column. Key findings include:
1) The AASC had improved workability over time compared to ordinary portland cement concrete, with minimal slump loss over 2 hours.
2) The temperature development in the AASC column was similar to a blended cement column and slower than an ordinary portland cement column, with a smaller temperature difference between the interior and exterior.
3) The compressive strength of the AASC column was identical to ordinary portland cement concrete and stronger than blended cement concrete at 28 and 91 days.
4) Embedded strain gauges
COMPRESSIVE STRENGTH AND CARBONATION OF SEA WATER CURED BLENDED CONCRETE IAEME Publication
This paper investigates the influence of sea water on pre-cast concrete containing
industrial by-product materials such as fly ash (FA) and silpozz. The mix design is targeted for
M30 grade concrete. Ten concrete mixtures were designed to have the same degree of
workability with water to cementitious material ratio of 0.43. The studied parameters include
the compressive strength of normal water curing (NWC) and sea water curing (SWC) samples
after 28 days of NWC for 7, 28, 90, 180 and 365 days curing period. The carbonation depth of
concrete samples for 28, 90, 180 and 365 days SWC after 28 days of NWC was measured. It
was found that the higher the FA content the higher is the carbonation process occurred. The
percentage increase in compressive strength for blended cement concrete in NWC is better
than the samples in SWC after 28 days of NWC
The document presents research on the effect of potassium chloride (KCl) on blended cement concrete (BCC). Tests were conducted on BCC with KCl concentrations ranging from 0.5 to 14 g/l added to deionized water. The results showed that increasing KCl concentration caused retardation of initial and final cement setting times. Compressive strengths of BCC at 28 and 90 days generally increased with higher KCl concentrations, with a significant strength increase observed at 10 g/l KCl. Chloride ion permeability of BCC decreased as KCl concentration increased. X-ray diffraction analysis was performed on BCC with 10 g/l KCl to deionized water.
Experimental Studies on the Prediction of Corrosion Levels in Reinforced TMT ...IRJET Journal
The document summarizes experimental studies on predicting corrosion levels in reinforced TMT bars in normal vibrated concrete (NVC) and self-consolidating concrete (SCC) exposed to a marine environment. Specimens of NVC and SCC with TMT bars embedded were immersed in de-ionized water with varying concentrations of NaCl and MgSO4 for curing periods of 28, 45, 60, and 90 days. Corrosion levels in the TMT bars after curing were then predicted by measuring potential differences between points on the specimens using a saturated calomel electrode and open circuit potential method. The studies aimed to investigate corrosion levels in TMT bars in NVC and SCC exposed to the marine environment
This paper presents the findings of an investigation on the compressive strength of concrete containing
Groundnut Husk Ash (GHA) blended with Rice Husk Ash (RHA) and its resistance to acid aggression, as well
as regression models of the concrete resistance in acidic environment. The GHA and RHA used were obtained
by controlled burning of groundnut husk and rice husk, respectively in a kiln to a temperature of 600 oC, and
after allowing cooling, sieved through sieve 75 µm and characterized. The compressive strength of GHA-RHAConcrete
was investigated at replacement levels of 0, 10, 20, 30 and 40 %, respectively by weight of cement. A
total of seventy five 150 mm cubes of GHA-RHA-Concrete grade 20 were tested for compressive strength at 3,
7, 28, 60 and 90 days of curing. Also, thirty 100 mm cubes were exposed to attack from 10 % concentration of
diluted solution of sulphuric acid (H2SO4) and nitric acid (HNO3), respectively and the concrete resistance was
also modeled using Minitab statistical software to establish regression models. The result of the investigations
showed that the compressive strength of the concrete decreased with increase in GHA-RHA content. However
15 % replacement with GHA-RHA was considered as optimum for structural concrete. The use of GHA
admixed with 10 % RHA in concrete improved its resistance against sulphuric and nitric acids aggression. The
average weight loss of GHA-RHA- concrete after 28 days of exposure in sulphuric acid and nitric acid were
11.6 % and 11.7 %, respectively as opposed to 22.4 % and 15.1 %, respectively for plain Portland cement
concrete. The regression models of GHA-RHA-Concrete for resistance against sulphuric and nitric acids were
developed with R2
values of 0.668 and 0.655, respectively and were adequate for prediction of the sensitivities
of pozzolanic activity of GHA-RHA in acidic environment.
This document presents the results of a study on the drying shrinkage of concrete made with three different cement types: ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Specimens were cured in normal water or artificial seawater for periods up to 365 days. The study found that PPC and PSC concretes experienced lower drying shrinkage compared to OPC concrete in both curing conditions. Additionally, blended cement concretes exhibited better workability than OPC concrete. The improved performance of blended cement composites is attributed to the pozzolanic reactions and filler effect of supplementary cementitious materials in PPC and PSC.
A Review On Development Of Flyash Based High Strength Geopolymer Concretecedmmantc5411
Geopolymer concrete is the latest development in the field of concrete technology and it is still
developing. Geopolymers are inorganic, stable, hard and non-inflammable binder. The application of
geopolymer binder are in fire resistance fiber composite, sealant industry, tooling aeronautics SPF aluminium,
foundry equipment’s, radioactive toxic waste, ceramic, bricks and other precast concrete. The current review is
aims to put forward the development in geopolymer concrete for the production high strength geopolymer
concrete having strength more than 90MPa. The development of high strength concrete is aimed to reduce
structural member sizes and for economical construction in case of long span bridges and tall buildings. Also
the use flyash in concrete to reduce green gas house emission into the atmosphere by reducing cement usage
This document studies the suitability of using incinerated sewage sludge ash (ISSA) to produce geopolymer concrete as a partial replacement for fly ash. Key findings include:
1) XRF testing showed that ISSA has high concentrations of SiO2 and Al2O3 similar to fly ash, making it a potential candidate for geopolymer concrete.
2) Concrete made with only ISSA did not develop significant strength, but strength decreased gradually as ISSA percentage increased in mixes partially replacing fly ash up to 20%.
3) Concrete with up to 15% ISSA replacement was considered average quality and absorption, allowing potential use for less strength-critical applications.
4)
This document summarizes a study on the strength and shrinkage properties of alkali-activated slag concrete (AASC) placed in a large concrete column. Key findings include:
1) The AASC had improved workability over time compared to ordinary portland cement concrete, with minimal slump loss over 2 hours.
2) The temperature development in the AASC column was similar to a blended cement column and slower than an ordinary portland cement column, with a smaller temperature difference between the interior and exterior.
3) The compressive strength of the AASC column was identical to ordinary portland cement concrete and stronger than blended cement concrete at 28 and 91 days.
4) Embedded strain gauges
COMPRESSIVE STRENGTH AND CARBONATION OF SEA WATER CURED BLENDED CONCRETE IAEME Publication
This paper investigates the influence of sea water on pre-cast concrete containing
industrial by-product materials such as fly ash (FA) and silpozz. The mix design is targeted for
M30 grade concrete. Ten concrete mixtures were designed to have the same degree of
workability with water to cementitious material ratio of 0.43. The studied parameters include
the compressive strength of normal water curing (NWC) and sea water curing (SWC) samples
after 28 days of NWC for 7, 28, 90, 180 and 365 days curing period. The carbonation depth of
concrete samples for 28, 90, 180 and 365 days SWC after 28 days of NWC was measured. It
was found that the higher the FA content the higher is the carbonation process occurred. The
percentage increase in compressive strength for blended cement concrete in NWC is better
than the samples in SWC after 28 days of NWC
The document presents research on the effect of potassium chloride (KCl) on blended cement concrete (BCC). Tests were conducted on BCC with KCl concentrations ranging from 0.5 to 14 g/l added to deionized water. The results showed that increasing KCl concentration caused retardation of initial and final cement setting times. Compressive strengths of BCC at 28 and 90 days generally increased with higher KCl concentrations, with a significant strength increase observed at 10 g/l KCl. Chloride ion permeability of BCC decreased as KCl concentration increased. X-ray diffraction analysis was performed on BCC with 10 g/l KCl to deionized water.
Experimental Studies on the Prediction of Corrosion Levels in Reinforced TMT ...IRJET Journal
The document summarizes experimental studies on predicting corrosion levels in reinforced TMT bars in normal vibrated concrete (NVC) and self-consolidating concrete (SCC) exposed to a marine environment. Specimens of NVC and SCC with TMT bars embedded were immersed in de-ionized water with varying concentrations of NaCl and MgSO4 for curing periods of 28, 45, 60, and 90 days. Corrosion levels in the TMT bars after curing were then predicted by measuring potential differences between points on the specimens using a saturated calomel electrode and open circuit potential method. The studies aimed to investigate corrosion levels in TMT bars in NVC and SCC exposed to the marine environment
This paper presents the findings of an investigation on the compressive strength of concrete containing
Groundnut Husk Ash (GHA) blended with Rice Husk Ash (RHA) and its resistance to acid aggression, as well
as regression models of the concrete resistance in acidic environment. The GHA and RHA used were obtained
by controlled burning of groundnut husk and rice husk, respectively in a kiln to a temperature of 600 oC, and
after allowing cooling, sieved through sieve 75 µm and characterized. The compressive strength of GHA-RHAConcrete
was investigated at replacement levels of 0, 10, 20, 30 and 40 %, respectively by weight of cement. A
total of seventy five 150 mm cubes of GHA-RHA-Concrete grade 20 were tested for compressive strength at 3,
7, 28, 60 and 90 days of curing. Also, thirty 100 mm cubes were exposed to attack from 10 % concentration of
diluted solution of sulphuric acid (H2SO4) and nitric acid (HNO3), respectively and the concrete resistance was
also modeled using Minitab statistical software to establish regression models. The result of the investigations
showed that the compressive strength of the concrete decreased with increase in GHA-RHA content. However
15 % replacement with GHA-RHA was considered as optimum for structural concrete. The use of GHA
admixed with 10 % RHA in concrete improved its resistance against sulphuric and nitric acids aggression. The
average weight loss of GHA-RHA- concrete after 28 days of exposure in sulphuric acid and nitric acid were
11.6 % and 11.7 %, respectively as opposed to 22.4 % and 15.1 %, respectively for plain Portland cement
concrete. The regression models of GHA-RHA-Concrete for resistance against sulphuric and nitric acids were
developed with R2
values of 0.668 and 0.655, respectively and were adequate for prediction of the sensitivities
of pozzolanic activity of GHA-RHA in acidic environment.
This document presents the results of a study on the drying shrinkage of concrete made with three different cement types: ordinary Portland cement (OPC), Portland pozzolana cement (PPC), and Portland slag cement (PSC). Specimens were cured in normal water or artificial seawater for periods up to 365 days. The study found that PPC and PSC concretes experienced lower drying shrinkage compared to OPC concrete in both curing conditions. Additionally, blended cement concretes exhibited better workability than OPC concrete. The improved performance of blended cement composites is attributed to the pozzolanic reactions and filler effect of supplementary cementitious materials in PPC and PSC.
A Review On Development Of Flyash Based High Strength Geopolymer Concretecedmmantc5411
Geopolymer concrete is the latest development in the field of concrete technology and it is still
developing. Geopolymers are inorganic, stable, hard and non-inflammable binder. The application of
geopolymer binder are in fire resistance fiber composite, sealant industry, tooling aeronautics SPF aluminium,
foundry equipment’s, radioactive toxic waste, ceramic, bricks and other precast concrete. The current review is
aims to put forward the development in geopolymer concrete for the production high strength geopolymer
concrete having strength more than 90MPa. The development of high strength concrete is aimed to reduce
structural member sizes and for economical construction in case of long span bridges and tall buildings. Also
the use flyash in concrete to reduce green gas house emission into the atmosphere by reducing cement usage
This document discusses microcracking and strength development in alkali activated slag concrete (AASC) subjected to different curing regimes. The main points are:
1) AASC cured without moist curing ("exposed") exhibited higher levels of microcracking compared to AASC with moist curing ("bath" or "sealed"), as measured by surface crack detection, water sorptivity, and mercury intrusion porosimetry tests.
2) Exposed AASC also showed significantly reduced compressive strength development compared to bath or sealed cured AASC. Strength of exposed AASC was 54% and 41% lower than bath and sealed AASC at 365 days.
3) Microcracking in
Experimental Investigations on Fresh Properties of Binary and Ternary Blended...AbdulRazakBH
Abstract--- Binder-chemical admixture compatibility plays a vital role in deciding the performance of concrete especially in the fresh state. Optimum dosage of chemical admixture is helpful in controlling various fresh properties of Self Compacting Concrete(SCC) and avoiding the problems of segregation and bleeding in blended concrete with mineral admixtures such as Ground granulated Blast Furnace Slag(GGBS) and Alccofine(Ultrafine GGBS). The study focusses on optimization of chemical admixture dosage for binary and ternary blended concrete for the production of SCC. Various combinations of binary blended concrete and ternary blended concrete along with control mix(only OPC) are tested for workability properties for passing ability, filling ability and and resistance to segregation(V-Funnel Time). It was observed that concrete containing higher GGBS required lesser dosage of chemical admixture for satisfying workability properties as per EFNAARC guidelines. Alccofinewas added at 5% to compensate for hardened properties.
Keywords--- Ground Granulated Blast Furnace Slag (GGBS), Alccofine, Self Compacting Concrete (SCC).
This paper investigates the workability and mechanical properties of concrete containing alkali-activated slag as the binder. Two types of activators were used: sodium hydroxide with sodium carbonate, and sodium silicate with hydrated lime. The fresh and hardened concrete properties of these alkali-activated slag concretes were compared to ordinary portland cement concrete. The results showed that concrete activated with powdered sodium silicate and lime had minimal slump loss over 2 hours and achieved similar 1-day compressive strengths as portland cement concrete when cured at normal temperatures. However, it exhibited higher drying shrinkage. Overall, alkali-activated slag concrete shows potential as a viable alternative to portland cement concrete.
An Experimental Study on Structural Grade Concrete Using Multi Mineral Admixt...IJERD Editor
Supplementary cementitious material (SCM) such as fly ash, ground granulated blast furnace slag
sand silica fume are extensively used in construction. A partial replacement of cement by mineral admixtures
such as, fly ash, GGBFS, silica fume (SF) in concrete mixes would help to overcome these problems and lead to
improvement in the durability of concrete. In this thesis of work, an attempt has been made to study the
mechanical properties of structural grade concrete using ternary blend.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
This document summarizes an experiment investigating the electrochemical behavior of carbon steel used for nuclear reactor containment buildings. Potentiodynamic, potentiostatic, and galvanostatic polarization techniques were used to study the steel's behavior in Ca(OH)2 solutions with varying NaCl concentrations. It was found that pitting occurred on the steel in solutions above a certain chloride concentration threshold that decreased with increasing chloride levels. Galvanostatic tests determined the chloride threshold conditions for depassivation of the pre-passivated steel. Optical microscopy of polarized samples confirmed localized corrosion above the threshold.
The document summarizes an experimental study on the effect of salt water on the compressive strength of concrete. Concrete cubes were cast using both fresh water and salt water (35g of salts per liter of water), and cured for 7, 14, and 28 days. The compressive strength was then tested. The results showed that concrete cubes cast and cured with salt water had slightly higher compressive strengths compared to those cast and cured with fresh water at all ages. At 28 days, the compressive strengths were 39.12 MPa for fresh water cubes and 41.34 MPa for salt water cubes. The study concluded that there is no reduction and even a small increase in compressive strength when salt water is used for casting and
Fresh, Strength and Durability Characteristics of Binary and Ternary Blended ...AbdulRazakBH
Abstract: Paper Mineral admixtures being the economical alternatives to Ordinary Portland Cement (OPC) for various normal and special concretes induce desirable properties to concrete such as higher flow, low heat of hydration, higher strength gain and enhanced durability. Ground granulated blast furnace slag(GGBFS) being one of the largely used mineral admixture alongside Fly Ash as supplementary cementitious material in concrete contributes to enhanced durability properties and low heat of hydration. Various replacement percentages of GGBS at 30%, 40%, 50% and 60% are used in binary blended Self compacting concrete(SCC) in the present study. At 40% replacement level, SCC exhibited improved workability, strength and durability properties. Alccofine(Ultrafine GGBS) used in ternary blended SCC enhanced early strength gain without affecting workability of SCC to a significant extent.
Keywords : Ground granulated blast furnace slag(GGBFS), Alccofine, Ordinary Portland cement(OPC)
The document discusses concrete durability strategies for the Rion-Antirion Bridge project in Greece, which requires concrete structures to withstand corrosion for 120 years in a marine environment. To achieve this, high-quality concrete was used with specifications exceeding contractual requirements. Testing showed the concrete had low chloride ion permeability and diffusion coefficients, validating its ability to prevent corrosion over 120 years. Strategies included using slag cement, low water-to-cement ratios, and increased concrete covers in more exposed zones to protect reinforcing steel from chlorides.
This document analyzes the effects of alkaline and acid solutions on the mechanical properties of glass/epoxy composites. It finds that:
1) Immersion in hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions decreases the flexural strength and modulus of the composites over time.
2) The alkaline sodium hydroxide solution promotes a higher decrease in flexural properties than the acid hydrochloric solution.
3) Both solutions also decrease the impact strength of the composites with increased exposure time, with the alkaline solution again having a greater effect.
This document discusses niobium-stabilized alloys used for steam reformer tubes. Steam reforming is a process that upgrades petroleum byproducts using catalytic reforming in tubes suspended in a furnace. Conventional materials like stainless steel are susceptible to creep from high temperatures and pressures. Niobium-stabilized alloys have improved creep resistance and allow for higher operating temperatures and pressures. The microstructure and composition of these alloys contributes to their strength, with columnar grains and a stoichiometric carbon to niobium ratio providing precipitation strengthening. These alloys enable more efficient reforming with thinner tube walls and greater catalyst packing density.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
Effect of nano-silica on the chemical durability and mechanical performance ...Ghassan Alhamdany
The document summarizes a study that investigated the effect of nano-silica on the chemical durability and mechanical performance of fly ash-based geopolymer concrete. Four types of geopolymer concrete with two types of fly ash, with and without nano-silica, were produced and subjected to sulfuric acid, magnesium sulfate, and seawater solutions. The study found that fly ash-based geopolymer concretes showed superior resistance to chemical attacks compared to ordinary Portland cement concrete. Among the chemical environments, sulfuric acid was the most aggressive. The addition of nano-silica improved both the durability and residual mechanical strength of the fly ash-based geopolymer concretes due to lower porosity
This document contains a declaration for a thesis submitted by Ng Ping Chew in fulfillment of the requirements for a Master's degree in Civil Engineering from Universiti Teknologi Malaysia. Ng declares that the thesis titled "Comparison of Creep and Shrinkage Using Different Code of Practice" does not contain any confidential information and agrees for it to be published as open access. The declaration is certified by Ng's supervisor, Assoc. Prof. Ir. Dr. Wahid Omar.
Experimental study of effects of potassium carbonate on strength parameters o...IAEME Publication
This study examines the effects of potassium carbonate (K2CO3) on the strength properties of plain concrete. Concrete specimens were produced with K2CO3 added at different percentages by weight of cement (2%, 2.2%, 2.4%, 2.6%, and 3%). The specimens were tested for compressive, flexural, and split tensile strengths at various ages. Results showed strengths increased up to 2.6% K2CO3 addition, but decreased with 3% addition. The optimum K2CO3 percentage was found to be 2.6%, as it improved strengths without harming concrete properties.
Effect of Waste Steel Slag and Silica Fume on Mechanical Properties of High S...IRJET Journal
The document discusses the effect of replacing fine aggregate with steel slag and adding silica fume on the mechanical properties of high strength self-compacting concrete. Concrete mixtures with 0-40% replacement of fine aggregate by steel slag and 10% addition of silica fume were tested. Test results showed that compressive strength, splitting tensile strength, and flexural strength increased with higher percentages of steel slag replacement and increased curing time up to 56 days. Replacing fine aggregate with steel slag and adding silica fume improved the mechanical properties of high strength self-compacting concrete.
Short term properties of High Calcium Flyashbased Geopolymer binderIOSRJMCE
The past decades of research is diverted primarily in making concrete without cement or atleast partially replacing by suitable alternatives. For its availability and problems associated with, flyash has been given priority to use in concrete in high volume or total replacement of cement resulting in geopolymer concrete using activated flyash of low calcium type as the source material. However, few are dealt on the high calcium flyash that too mainly on achieving the required compressive strength and not much on the short term engineering properties like consistency and setting characteristicseven though itis essential to establish the time available for placing, compaction and transport of geopolymer. Therefore, a fundamental study on the setting characteristics and strength development of high calcium flyash based geopolymer with varying concentration of Sodium hydroxide(8-14M),varying liquid ratios (1.5-3.0) of the activator and curing at ambient and 65oCtemperature is made.It is observed that the consistency of flyash based geopolymer increases with increase of concentration of NaOH and is not at all influenced by the liquid ratios considered but, the setting time is reduced by oven curing obviously. Also, the mortar strength is atleast 10% more for hot curing than ambient curing.
Biological and mechanical properties of pmma based bioactive bone cements bio...Mohamed Moh
The document evaluates the mechanical properties and apatite-forming ability of PMMA bone cements containing varying amounts of wollastonite. Setting times, maximum temperature reached during setting, and compressive strength decreased as wollastonite content increased from 0% to 68%. Cements containing 19-39% wollastonite met the minimum compressive strength requirement of 70 MPa. XRD and SEM analysis showed apatite formation on the surfaces of cements containing 39-49% wollastonite after 21 days of immersion in simulated body fluid, indicating their potential bioactivity.
The document summarizes research on producing hydroxyapatite (HAp) prototypes from gypsum/polyvinyl alcohol (PVA) composites. Porous gypsum blocks were produced by adding PVA to gypsum powder and molding. The blocks were then converted to HAp through chemical reaction in ammonium phosphate and hydroxide solutions. Characterization techniques confirmed the structures of gypsum, PVA composite, and final HAp. HAp prototypes after 36 hours of reaction showed predominant HAp peaks via XRD and EDS identified calcium and phosphorus. The HAp had high porosity (80%) and low compression strength (3.5 MPa) suitable for bone growth.
This document summarizes a study that investigated the surface reactivity and biocompatibility of SiO2–TiO2–CaO–Na2O/SrO bioceramics as a function of structure and incubation time in simulated body fluid. Glass and ceramic samples with varying sodium and strontium concentrations were characterized, incubated in simulated body fluid for up to 30 days, and evaluated for calcium phosphate deposition and changes in surface morphology. Cell culture analysis also assessed the effect on cell viability. The addition of strontium reduced solubility and calcium phosphate precipitation compared to sodium-containing materials. Crystallization also decreased reactivity compared to amorphous structures.
This document discusses microcracking and strength development in alkali activated slag concrete (AASC) subjected to different curing regimes. The main points are:
1) AASC cured without moist curing ("exposed") exhibited higher levels of microcracking compared to AASC with moist curing ("bath" or "sealed"), as measured by surface crack detection, water sorptivity, and mercury intrusion porosimetry tests.
2) Exposed AASC also showed significantly reduced compressive strength development compared to bath or sealed cured AASC. Strength of exposed AASC was 54% and 41% lower than bath and sealed AASC at 365 days.
3) Microcracking in
Experimental Investigations on Fresh Properties of Binary and Ternary Blended...AbdulRazakBH
Abstract--- Binder-chemical admixture compatibility plays a vital role in deciding the performance of concrete especially in the fresh state. Optimum dosage of chemical admixture is helpful in controlling various fresh properties of Self Compacting Concrete(SCC) and avoiding the problems of segregation and bleeding in blended concrete with mineral admixtures such as Ground granulated Blast Furnace Slag(GGBS) and Alccofine(Ultrafine GGBS). The study focusses on optimization of chemical admixture dosage for binary and ternary blended concrete for the production of SCC. Various combinations of binary blended concrete and ternary blended concrete along with control mix(only OPC) are tested for workability properties for passing ability, filling ability and and resistance to segregation(V-Funnel Time). It was observed that concrete containing higher GGBS required lesser dosage of chemical admixture for satisfying workability properties as per EFNAARC guidelines. Alccofinewas added at 5% to compensate for hardened properties.
Keywords--- Ground Granulated Blast Furnace Slag (GGBS), Alccofine, Self Compacting Concrete (SCC).
This paper investigates the workability and mechanical properties of concrete containing alkali-activated slag as the binder. Two types of activators were used: sodium hydroxide with sodium carbonate, and sodium silicate with hydrated lime. The fresh and hardened concrete properties of these alkali-activated slag concretes were compared to ordinary portland cement concrete. The results showed that concrete activated with powdered sodium silicate and lime had minimal slump loss over 2 hours and achieved similar 1-day compressive strengths as portland cement concrete when cured at normal temperatures. However, it exhibited higher drying shrinkage. Overall, alkali-activated slag concrete shows potential as a viable alternative to portland cement concrete.
An Experimental Study on Structural Grade Concrete Using Multi Mineral Admixt...IJERD Editor
Supplementary cementitious material (SCM) such as fly ash, ground granulated blast furnace slag
sand silica fume are extensively used in construction. A partial replacement of cement by mineral admixtures
such as, fly ash, GGBFS, silica fume (SF) in concrete mixes would help to overcome these problems and lead to
improvement in the durability of concrete. In this thesis of work, an attempt has been made to study the
mechanical properties of structural grade concrete using ternary blend.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
This document summarizes an experiment investigating the electrochemical behavior of carbon steel used for nuclear reactor containment buildings. Potentiodynamic, potentiostatic, and galvanostatic polarization techniques were used to study the steel's behavior in Ca(OH)2 solutions with varying NaCl concentrations. It was found that pitting occurred on the steel in solutions above a certain chloride concentration threshold that decreased with increasing chloride levels. Galvanostatic tests determined the chloride threshold conditions for depassivation of the pre-passivated steel. Optical microscopy of polarized samples confirmed localized corrosion above the threshold.
The document summarizes an experimental study on the effect of salt water on the compressive strength of concrete. Concrete cubes were cast using both fresh water and salt water (35g of salts per liter of water), and cured for 7, 14, and 28 days. The compressive strength was then tested. The results showed that concrete cubes cast and cured with salt water had slightly higher compressive strengths compared to those cast and cured with fresh water at all ages. At 28 days, the compressive strengths were 39.12 MPa for fresh water cubes and 41.34 MPa for salt water cubes. The study concluded that there is no reduction and even a small increase in compressive strength when salt water is used for casting and
Fresh, Strength and Durability Characteristics of Binary and Ternary Blended ...AbdulRazakBH
Abstract: Paper Mineral admixtures being the economical alternatives to Ordinary Portland Cement (OPC) for various normal and special concretes induce desirable properties to concrete such as higher flow, low heat of hydration, higher strength gain and enhanced durability. Ground granulated blast furnace slag(GGBFS) being one of the largely used mineral admixture alongside Fly Ash as supplementary cementitious material in concrete contributes to enhanced durability properties and low heat of hydration. Various replacement percentages of GGBS at 30%, 40%, 50% and 60% are used in binary blended Self compacting concrete(SCC) in the present study. At 40% replacement level, SCC exhibited improved workability, strength and durability properties. Alccofine(Ultrafine GGBS) used in ternary blended SCC enhanced early strength gain without affecting workability of SCC to a significant extent.
Keywords : Ground granulated blast furnace slag(GGBFS), Alccofine, Ordinary Portland cement(OPC)
The document discusses concrete durability strategies for the Rion-Antirion Bridge project in Greece, which requires concrete structures to withstand corrosion for 120 years in a marine environment. To achieve this, high-quality concrete was used with specifications exceeding contractual requirements. Testing showed the concrete had low chloride ion permeability and diffusion coefficients, validating its ability to prevent corrosion over 120 years. Strategies included using slag cement, low water-to-cement ratios, and increased concrete covers in more exposed zones to protect reinforcing steel from chlorides.
This document analyzes the effects of alkaline and acid solutions on the mechanical properties of glass/epoxy composites. It finds that:
1) Immersion in hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions decreases the flexural strength and modulus of the composites over time.
2) The alkaline sodium hydroxide solution promotes a higher decrease in flexural properties than the acid hydrochloric solution.
3) Both solutions also decrease the impact strength of the composites with increased exposure time, with the alkaline solution again having a greater effect.
This document discusses niobium-stabilized alloys used for steam reformer tubes. Steam reforming is a process that upgrades petroleum byproducts using catalytic reforming in tubes suspended in a furnace. Conventional materials like stainless steel are susceptible to creep from high temperatures and pressures. Niobium-stabilized alloys have improved creep resistance and allow for higher operating temperatures and pressures. The microstructure and composition of these alloys contributes to their strength, with columnar grains and a stoichiometric carbon to niobium ratio providing precipitation strengthening. These alloys enable more efficient reforming with thinner tube walls and greater catalyst packing density.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
Effect of nano-silica on the chemical durability and mechanical performance ...Ghassan Alhamdany
The document summarizes a study that investigated the effect of nano-silica on the chemical durability and mechanical performance of fly ash-based geopolymer concrete. Four types of geopolymer concrete with two types of fly ash, with and without nano-silica, were produced and subjected to sulfuric acid, magnesium sulfate, and seawater solutions. The study found that fly ash-based geopolymer concretes showed superior resistance to chemical attacks compared to ordinary Portland cement concrete. Among the chemical environments, sulfuric acid was the most aggressive. The addition of nano-silica improved both the durability and residual mechanical strength of the fly ash-based geopolymer concretes due to lower porosity
This document contains a declaration for a thesis submitted by Ng Ping Chew in fulfillment of the requirements for a Master's degree in Civil Engineering from Universiti Teknologi Malaysia. Ng declares that the thesis titled "Comparison of Creep and Shrinkage Using Different Code of Practice" does not contain any confidential information and agrees for it to be published as open access. The declaration is certified by Ng's supervisor, Assoc. Prof. Ir. Dr. Wahid Omar.
Experimental study of effects of potassium carbonate on strength parameters o...IAEME Publication
This study examines the effects of potassium carbonate (K2CO3) on the strength properties of plain concrete. Concrete specimens were produced with K2CO3 added at different percentages by weight of cement (2%, 2.2%, 2.4%, 2.6%, and 3%). The specimens were tested for compressive, flexural, and split tensile strengths at various ages. Results showed strengths increased up to 2.6% K2CO3 addition, but decreased with 3% addition. The optimum K2CO3 percentage was found to be 2.6%, as it improved strengths without harming concrete properties.
Effect of Waste Steel Slag and Silica Fume on Mechanical Properties of High S...IRJET Journal
The document discusses the effect of replacing fine aggregate with steel slag and adding silica fume on the mechanical properties of high strength self-compacting concrete. Concrete mixtures with 0-40% replacement of fine aggregate by steel slag and 10% addition of silica fume were tested. Test results showed that compressive strength, splitting tensile strength, and flexural strength increased with higher percentages of steel slag replacement and increased curing time up to 56 days. Replacing fine aggregate with steel slag and adding silica fume improved the mechanical properties of high strength self-compacting concrete.
Short term properties of High Calcium Flyashbased Geopolymer binderIOSRJMCE
The past decades of research is diverted primarily in making concrete without cement or atleast partially replacing by suitable alternatives. For its availability and problems associated with, flyash has been given priority to use in concrete in high volume or total replacement of cement resulting in geopolymer concrete using activated flyash of low calcium type as the source material. However, few are dealt on the high calcium flyash that too mainly on achieving the required compressive strength and not much on the short term engineering properties like consistency and setting characteristicseven though itis essential to establish the time available for placing, compaction and transport of geopolymer. Therefore, a fundamental study on the setting characteristics and strength development of high calcium flyash based geopolymer with varying concentration of Sodium hydroxide(8-14M),varying liquid ratios (1.5-3.0) of the activator and curing at ambient and 65oCtemperature is made.It is observed that the consistency of flyash based geopolymer increases with increase of concentration of NaOH and is not at all influenced by the liquid ratios considered but, the setting time is reduced by oven curing obviously. Also, the mortar strength is atleast 10% more for hot curing than ambient curing.
Biological and mechanical properties of pmma based bioactive bone cements bio...Mohamed Moh
The document evaluates the mechanical properties and apatite-forming ability of PMMA bone cements containing varying amounts of wollastonite. Setting times, maximum temperature reached during setting, and compressive strength decreased as wollastonite content increased from 0% to 68%. Cements containing 19-39% wollastonite met the minimum compressive strength requirement of 70 MPa. XRD and SEM analysis showed apatite formation on the surfaces of cements containing 39-49% wollastonite after 21 days of immersion in simulated body fluid, indicating their potential bioactivity.
The document summarizes research on producing hydroxyapatite (HAp) prototypes from gypsum/polyvinyl alcohol (PVA) composites. Porous gypsum blocks were produced by adding PVA to gypsum powder and molding. The blocks were then converted to HAp through chemical reaction in ammonium phosphate and hydroxide solutions. Characterization techniques confirmed the structures of gypsum, PVA composite, and final HAp. HAp prototypes after 36 hours of reaction showed predominant HAp peaks via XRD and EDS identified calcium and phosphorus. The HAp had high porosity (80%) and low compression strength (3.5 MPa) suitable for bone growth.
This document summarizes a study that investigated the surface reactivity and biocompatibility of SiO2–TiO2–CaO–Na2O/SrO bioceramics as a function of structure and incubation time in simulated body fluid. Glass and ceramic samples with varying sodium and strontium concentrations were characterized, incubated in simulated body fluid for up to 30 days, and evaluated for calcium phosphate deposition and changes in surface morphology. Cell culture analysis also assessed the effect on cell viability. The addition of strontium reduced solubility and calcium phosphate precipitation compared to sodium-containing materials. Crystallization also decreased reactivity compared to amorphous structures.
1) The document investigates the compressive strength and carbonation of pre-cast concrete containing fly ash and silpozz cured in sea water over different time periods.
2) Ten concrete mixtures were designed to study the effects of curing in normal water versus sea water on compressive strength over 7, 28, 90, 180, and 365 days. Carbonation depth was also measured for sea water cured samples.
3) Results found that blended cement concretes with higher fly ash content had higher carbonation. Compressive strength gain was better for normal water curing than sea water curing after 28 days.
Perovskite Crystals: A Bright Future in Solar TechnologyReid Barton
1) The student created perovskite crystal solar cells using different precursor solutions and measured their voltage outputs. Cells using a 2:1 ratio of formamidinium chloride to lead iodide performed best, achieving up to 520 mV.
2) A tandem cell combining perovskite and silicon layers performed better than either individually, demonstrating potential for improved efficiencies.
3) The higher chloride concentration in the optimal precursor solution likely increased the crystal's band gap, resulting in a higher output voltage. While rudimentary, the experiments provided insight into effective precursor compositions.
This document presents research on the compressive strength of bamboo leaf ash (BLA) blended cement concrete cured in different sulphate environments. Concrete cubes with 0%, 5%, 10%, and 15% replacement of cement with BLA were cured in water and sulphate solutions of varying concentrations for 21 and 28 days. Testing found that BLA concrete strengths generally increased with higher sulphate concentrations and longer curing times compared to plain cement concrete. Replacement of 10% cement with BLA produced the highest strengths. The results indicate BLA concrete has improved sulphate resistance and could be suitable for use in sulphate environments where early strength is not critical.
The Influence of Swine-Waste Biochar on the Early-Age Characteristics of Ceme...IJERA Editor
The purpose of this research was to investigate the influence of swine-waste biochar (SB) on the early-age characteristics of cement pastes. Using a water/binder ratio of 0.28, SB modified cement pastes were analyzed using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), flow, and Vicat setting tests. Notably, SB reduced the flow and initial setting times of SB modified cement pastes. Due to its porous and negatively charged surfaces, capillary water was adsorbed into the pores of the carbonaceous SB and this reduced the flow of the SB modified cement pastes. Furthermore, it is suspected that the reductions in initial setting times may have been because with the addition of water to the dry SB/cement binder mix, chemical reactions between the calcium cations from Portland cement and carboxylate anions from SB resulted in the development of Calcium Polycarboxylate Salts (C-P-S). Improvements in the properties of SB could enhance its applications in rapid-setting and flow-reducing concrete.
SIMONA CAVALU_Microstructure and bioactivity of acrylic bone cementsSimona Cavalu
Polymer-ceramic composites based on polymethyl methacrylate are widely used in orthopaedics as suture materials and
fixation devices due to their biocompatibility and ability to support bony growth (osteoconductive) and also bone bioactive
(to form a calcium phosphate layer on its surface). In this study are compared the microstructure, bioactivity and
biocompatibility of two different types of biocomposites: BIOLOS3®and ANTIBIOTIC SIMPLEX®. They are investigated in
vitro in simulated body fluid using electrochemical measurements, SEM microscopy and ATR-FTIR spectroscopy in order to
evaluate the properties of the surface layer.
IRJET - Electrophoretic Deposition of Calcium phosphate Ceramics over Dup...IRJET Journal
This document summarizes research on coating calcium phosphate ceramics onto duplex stainless steel using electrophoretic deposition. The coatings of hydroxyapatite (HAp) and tricalcium phosphate (TCP) were characterized. HAp was coated at voltages from 7.5V to 15V and times from 7.5 to 120 minutes. TCP was coated at voltages of 10V, 12.5V and 15V and times of 7.5 to 15 minutes. Coating morphology, composition, and adhesion were analyzed using SEM, EDS, and tape tests. HAp coatings showed different growth structures depending on voltage and time, while TCP coatings adhered best at 10V and 10 minutes. The growth mechanisms
Optimization of temperature imposed on activator before mixinginventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Study on effect of Alccofine & Fly ash addition on the Mechanical properties ...ijsrd.com
This paper presents the results of an experimental investigation carried out for M-70 Grad Concrete and to evaluate the compressive strength and Flexural Strength of Concrete. High Performance Concrete is made by partial replacement of cement by alccofine, fly ash, silica fume. In this study the Class F fly ash used in various proportions 20 to 35%, alccofine 4 to 14% and silica fume 4% to 14% by weight of cement. The mix proportions of concrete had a water binder ratio for Alccofine mix concrete 0.30 and Silica-fume mix concrete 0.32.super plasticizer was added based on the required degree of workability. The total binder content was 600 kg/m3. The concrete specimens were cured on normal moist curing under normal atmospheric temperature. The compressive strength was determined at 7 , 28 , 56 days and flexural strength was determined at 28 and 56 days The results indicate the concrete made with these proportions generally show excellent fresh and hardened properties. The addition of Alccofine, silica fume shows early strength gaining property and that of fly ash shows a long term strength. The ternary system that is Portland cement-fly ash-Alccofine concrete was found to increase the compressive strength of concrete on all age when compared to concrete made with Portland cement-fly ash-silica fume.
This document discusses the role of water in calcium carbonate fillers used in moisture-sensitive adhesives and sealants. It explains that calcium carbonate readily absorbs water from the environment due to the rearrangement of ions on its surface. This absorbed water can cause issues in moisture-curing formulations. The document recommends treating calcium carbonate with fatty acids to hydrophobize its surface and minimize water absorption. It provides details on the mechanism of fatty acid treatment and its effectiveness at improving water resistance of calcium carbonate over a range of humidity levels.
This document summarizes a study that compares the microstructure, bioactivity, and biocompatibility of two types of acrylic bone cements: BIOLOS3® and ANTIBIOTIC SIMPLEX®. Electrochemical measurements, SEM imaging, and FTIR spectroscopy were used to analyze the materials after incubation in simulated body fluid for up to 34 days. The results showed that ANTIBIOTIC SIMPLEX® developed a more intense mineralization layer on its surface, as evidenced by greater calcium phosphate formation and water uptake. Hemolysis testing also indicated ANTIBIOTIC SIMPLEX® had better blood compatibility. In conclusion, the antibiotic-containing cement demonstrated superior in vitro bioactivity and bi
Effects of Self Compacting Concrete Using the Discrete Models as Binary & Ter...theijes
The effect of using nanosized[4],[5] pozzolanic materials [1], [12], 14] like Fly ash(FA) [3], Metakeolin (MK) [8],Silica fume(SF)[6],Rise husk ash(RHA)[14],Ground granulated blust furnace slag (GGBFS)[2] etc. as partial replacement with dry weight of Ordinary Portland Cement(OPC) to enhance the strength, durability, workability of concrete. The test results of fresh and the hardened properties of Self compacting concrete (SCC)[8],[19] incorporating pozzolanic materials at various percentage by fixing the Water to Binder (i.e. powder)ratio(w/b) of 0.45. The effects of pozzolanic materials properties of SCC were investigated by comparing the test results. Various tests [4],[5],[9] were conducted on fresh SCC like the slump flow, L-box passing ability of the SCC mixtures and T500mm slump flow time were also done. Compressive strength test [9] along with the Initial surface absorption test(ISAT) and the Capillary suction test(CST)[7] were also performed on the hardened SCC[8]
This document discusses how the pore size distribution affects drying shrinkage in alkali-activated slag concrete (AASC) compared to ordinary Portland cement concrete (OPCC). The main points are:
1) AASC exhibited higher drying shrinkage than OPCC even though OPCC lost more moisture during drying.
2) The pore size distribution of AASC pastes showed a much higher proportion of pores in the mesopore region compared to OPC pastes.
3) The radius of pores where the meniscus forms during drying seems to be a more important factor for shrinkage than the total moisture loss. This supports the theory that capillary tensile forces from drying cause shrinkage.
geopolymer is a eco-friendly, popular and resourceful replacement of conventional concretre. there are different types of Geoplymer.In this case no uses of conventional concrete made it most unique and environment friendly.
Engineered Cementitious Composite (ECC), also called Strain Hardening Cement-based Composites (SHCC) or more popularly as bendable concrete, is an easily molded mortar-based composite reinforced with specially selected short random fibers, usually polymer fibers. Unlike regular concrete, ECC has a strain capacity in the range of 3–7%, compared to 0.01% for ordinary portland cement (OPC ...
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This document summarizes a study on the effects of using saturated porous blast furnace slag coarse aggregate in alkali-activated slag concrete (AAS). The study found that AAS containing the porous coarse aggregate had higher compressive strength and significantly less drying shrinkage compared to AAS made with normal weight coarse aggregate. The porous aggregate provided internal curing, with water slowly releasing inside the concrete to further hydrate the paste. Under drying conditions, AAS with porous aggregate showed 40% less shrinkage and higher strengths after 1 day compared to AAS with normal aggregate.
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2. How to cite this article: Cortés-Hernández DA, Acuña-Gutiérrez IO, Escobedo-Bocardo JC, Almanza-Robles JM, García-Álvarez G, et al. In vitro Bioactivity
Assessment of Novel Composites Based on Calcium Aluminate Cement. Res Dev Material Sci. 1(2). RDMS.000510. 2017. DOI: 10.31031/RDMS.2017.01.000510
Research & Development in Material Science
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Res Dev Material Sci
Compressive strength
Before compressive strength evaluation, samples were
immersed in SBF for 1, 7, 14 or 21 days at 37 °C. The compressive
load was applied at a crosshead speed of 0.5mm/min. The
mechanical strength evaluation was performed according to the
ASTM F 451[13].
Setting times
The initial and final setting times of cements were evaluated
using a Vicat needle (ASTM C 191) [14].
Results and Discussion
Figure 1: XRD patterns of composite surfaces before immersion
in SBF: 1a: CAC 5Pw; 1b: CAC 10Pw.
Figure 1 shows the XRD patterns of the surface composites (CAC
5Pw and CAC 10Pw) before immersion in SBF. Peaks corresponding
tonon-hydratedcalcium aluminate [JCPDS 070-0134; CaAl2
O4
] and
Friedel´s salt [JCPDS 089-52-94; (CaO)3
(Al2
O3
)(CaCl2
)(H2
O)10
]
wereobserved in both patterns (Figure 1a & 1b). It can be observed
that the intensity of the peaks corresponding to Friedel´s salt
decreased as the quantity of pseudowollastonite increased, this
fact is possibly due to a decrease in porosity of the composite
by the addition of pseudowollastonite. This salt is formed by the
reaction of CAC with the chloride ions of the aqueous solution [15].
In the XRD pattern corresponding of the CAC 10Pw (Figure 1b),
also pseudowollastonite [JCPDS 074-08-74; CaSiO3
] was detected.
No peaks corresponding to pseudowollastonite were observed on
the pattern of CAC 5Pw (Figure 1a) due to the sensibility of this
technique.
Figure 2: XRD patterns of composite surfaces after21 days of
immersion in SBF: 2a: CAC 5Pw; 2b: CAC 10Pw.
Figure 2 shows the XRD patterns of the surface composites
(CAC 5Pw and CAC 10Pw) after 21 days of immersion in SBF. Peaks
corresponding tonon-hydrated calcium aluminate [JCPDS 070-
0134; CaAl2
O4
], aluminum hydroxide [JCPDS 074-1775; Al(OH)3
]
and pseudowollastonite[JCPDS 074-08-74; CaSiO3
] were observed
in both patterns. Peaks corresponding to HA be observed in the
pattern corresponding to CAC 10Pw (Figure 2b). This compound
is formed in bioactive materials when they are exposed to SBF. As
observed, the increase in the amount of pseudowollastonite in the
composite increased the bioactivity of the material.
Figure 3: SEM images and EDS spectra of the surface composites before immersion in SBF: 3a: CAC 5 Pw; 3b: CAC 10 Pw; and after
21 days immersion in SBF: 3c: CAC 5Pw; 3d: CAC 10 Pw.
3. How to cite this article: Cortés-Hernández DA, Acuña-Gutiérrez IO, Escobedo-Bocardo JC, Almanza-Robles JM, García-Álvarez G, et al. In vitro Bioactivity
Assessment of Novel Composites Based on Calcium Aluminate Cement. Res Dev Material Sci. 1(2). RDMS.000510. 2017. DOI: 10.31031/RDMS.2017.01.000510
3/3
Res Dev Material SciResearch & Development in Material Science
Figure 3 shows SEM images and EDS spectra of the composites
(CAC 5Pw and CAC 10Pw) before and after 21 days of immersion
in SBF. Before immersion (Figure 3a & 3b), a rough surface was
observed on both composites. In the corresponding EDS spectra,
the presence of Al, Ca, Si and O, main elements of calcium aluminate
and pseudowollastonite was detected, which was corroborated by
XRD (Figure 1). Figures 3c & 3d correspond to the composites CAC
5Pw and CAC 10Pw after 21 days of immersion in SBF. It can be
observed in both SEM images that a thick and homogenous ceramic
layer, constituted by Ca, P-rich agglomerates, fact corroborated for
the corresponding EDS spectra, was formed in the surfacecements.
The Ca, P-rich layer was identified as HA by XRD (Figure 2). The
bioactivity of the cements increased as the pseudowollastonite
amount was increased.
Figure 4: Compressive strength of composites as a function of
immersion time in SBF.
Figure 4 shows the compressive strength of the composites as
a function of immersion time in SBF. As observed, the compressive
strength decreased as the pseudowollastonite content was
increased. The initial values of strength (1 day of immersion in
SBF) of cements were around 70MPa. After 21 days of immersion
in SBF composites (CAC 5Pw and CAC 10Pw) shows appropriates
mechanical properties. According to the ASTM F-451, a minimum
value of 70MPa is required for bone cements.
When comparing setting time of both cements, no significant
changes were observed in the initial (23 and 20min) and final (2.5
and 2.3min) setting times obtained for CAC 5Pw and CAC 10Pw,
respectively.
Conclusion
Novel composites based in calcium aluminate cement were
obtained. After 21 days of immersion in SBF a homogeneous and
thick apatite layer was observed on the surface cements (CAC 5Pw
and CAC 10Pw). A higher bioactivity was observed on cements
with content of 10% of pseudowollastonite. The cements showed
appropriate compressive strength. The results obtained indicate
that cements can be highly potential bone cements.
Acknowledgement
The authors gratefully acknowledge CONACYT, México for the
scholarship 219442 granted to I.O. Acuña Gutiérrez.
References
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