scholarly journals Effect of Metal Lathe Waste Addition on the Mechanical and Thermal Properties of Concrete

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2760
Author(s):  
Marcin Małek ◽  
Marta Kadela ◽  
Michał Terpiłowski ◽  
Tomasz Szewczyk ◽  
Waldemar Łasica ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Ph Value ◽  
Reference Sample ◽  
Mechanical And Thermal Properties ◽  
Fine Aggregate ◽  
Splitting Strength ◽  
Metal Chips ◽  
Tensile Splitting Strength

The amount of steel chips generated by lathes and CNC machines is 1200 million tons per year, and they are difficult to recycle. The effect of adding steel chips without pre-cleaning (covered with production lubricants and cooling oils) on the properties of concrete was investigated. Steel waste was added as a replacement for fine aggregate in the amounts of 5%, 10% and 15% of the cement weight, which correspond with 1.1%, 2.2% and 3.3% mass of all ingredients and 0.33%, 0.66% and 0.99% volume of concrete mix, respectively. The slump cone, air content, pH value, density, compressive strength, tensile strength, tensile splitting strength, elastic modulus, Poisson’s ratio and thermal parameters were tested. It was observed that with the addition of lathe waste, the density decreased, but mechanical properties increased. With the addition of 5%, 10% and 15% metal chips, compressive strength increased by 13.9%, 20.8% and 36.3% respectively compared to plain concrete; flexural strength by 7.1%, 12.7% and 18.2%; and tensile splitting strength by 4.2%, 33.2% and 38.4%. Moreover, it was determined that with addition of steel chips, thermal diffusivity was reduced and specific heat capacity increased. With the addition of 15% metal chips, thermal diffusivity was 25.2% lower than in the reference sample, while specific heat was 23.0% higher. No effect was observed on thermal conductivity.

scholarly journals The Effect of Mixing Technique and Prolonged Mixing Time on Strength Characteristics of Concrete

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1290
Author(s):  
Karol Urban ◽  
Alena Sicakova
Keyword(s):  
Compressive Strength ◽  
Mixing Time ◽  
Strength Properties ◽  
Recycled Concrete ◽  
Strength Characteristics ◽  
Concrete Aggregate ◽  
Splitting Strength ◽  
Mixing Method ◽  
Tensile Splitting Strength ◽  
The Impact

The experiment aims to test the triple mixing (3M) technique to produce the concrete with recycled concrete aggregate (RCA). Then, the impact prolonged mixing, representing the influence of delivery and discharge time in praxis, is analysed by the change in strength properties. Both the 28-day compressive strength and tensile splitting strength are evaluated in two aspects: the prolonged mixing time (0, 45 and 90 min after initial mixing), and the mixing method (normal and triple). Prolonged mixing time brought both the positive and negative changes in strength characteristics however the worst difference between initial mixing (0′) and 90′ minutes of mixing was only 8.4% for compressive strength and 8.5% for tensile splitting strength.

Mechanical Properties of Steam-Cured Concrete with Combined Mineral Admixtures

2010 ◽  
Vol 168-170 ◽  
pp. 1535-1538
Author(s):  
Zhi Min He ◽  
Jun Zhe Liu ◽  
Tian Hong Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Precast Concrete ◽  
High Volume ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Splitting Strength ◽  
High Volume Fly Ash ◽  
Tensile Splitting Strength

In precast concrete elements manufacturing, steam-cured concrete incorprating 30% mineral admixtures encountered the problem of too low demoulding compressive strength. To resolve it, this paper mainly studied the influence of mineral admixtures on the compressive strength, the tensile-splitting strength and the flexural strength of the steam-cured concrete. The experimental results indicated that, compared with steam-cured concrete incorprating mineral admixtures, the later strength of steam-cured concrete incorprating 0% mineral admixtures has lower increment degree and its increment of tensile-splitting strength and flexural strength inverted to some extent. The demoulding compressive strength is too low for the high volume fly ash concrete mixtures. The problem of too low demoulding compressive strength is solved by incorprating composites of ground blast furnace slag(GBFS) and fly ash. Different varieties of mineral admixture used in the concretes can produce a certain degree of potentiation.

scholarly journals Correlations between compressive strength and tensile strength of concrete for two-layers pavement with exposed aggregate

2014 ◽  
Vol 13 (4) ◽  
pp. 137-144
Author(s):  
Małgorzata Konopska-Piechurska ◽  
Wioletta Jackiewicz-Rek ◽  
Paweł Łukowski
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Aggregate Size ◽  
Bottom Layer ◽  
Concrete Pavement ◽  
Maximum Aggregate Size ◽  
Splitting Strength ◽  
Tensile Splitting Strength ◽  
Cylindrical Samples

In the paper the results of experiments on concrete pavement with exposed aggregate technology placed in two technological layers were presented. The following properties were measured: compressive strength, flexural strength by two methods: two-point loading and centre-point loading, tensile splitting strength of cubic and cylindrical samples. The study was performed for two type of concrete with a maximum aggregate size Dmax 8 mm (concrete applied to the upper layer of concrete pavement - GWB) and Dmax 22 mm (concrete used for the bottom layer - DWB). After the analysis of the tests, the correlations between compressive strength and tensile strength, measured by flexural strength and tensile splitting strength, were determined for the used two-layers concrete pavement with exposed aggregate depending on applied Dmax.

Mechanical Behaviors of Structural Concrete Using Recycled Aggregates from Repeatedly Recycling Waste Concrete

2012 ◽  
Vol 450-451 ◽  
pp. 1379-1382 ◽  
Author(s):  
Jin Cai Feng ◽  
Ping Hua Zhu ◽  
Qun Xia
Keyword(s):  
Compressive Strength ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Mechanical Behaviors ◽  
Structural Concrete ◽  
Waste Concrete ◽  
Fine Aggregates ◽  
Tensile Splitting Strength

This paper reports an expermiental study on mechanical behaviors of structural concrete using recycled aggregates from repeatedly recycling waste concrete. Five series of natural aggregate concretes with compressive strengths of 25MPa, 30MPa, 40MPa, 50MPa and 60MPa were used as recycled coarse and fine aggregates to produce recycled concrete with an objective compressive strength of 30MPa after they were cured for 28d. These recycled concretes were used as aggregates to produce concrete with the same objective compressive strength of 30MPa. The cycles were carried on until the indices evaluating the quality of recycled coarse or fine aggregate exceeded the tolerance. The mechanical behaviors of these concrete were tested. The results indicates that that with the increase of the cyclic number, the mechanical properties of recycled concrete, including compressive strength, tensile splitting strength, modulus of elasticity, gradually stabilize after obviously decreaing in the first instance.

Thermophysical Properties of Metakaolin Geopolymers Based on Na2SiO3/NaOH Ratio

2018 ◽  
Vol 280 ◽  
pp. 487-493 ◽  
Author(s):  
Ain Jaya Nur ◽  
Yun Ming Liew ◽  
Mohd Mustafa Abdullah Al Bakri ◽  
Cheng Yong Heah
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Sodium Silicate ◽  
Thermophysical Properties ◽  
Insulating Material ◽  
Thermal Insulating ◽  
High Specific Heat ◽  
Alkaline Activator

In the present work, the effect of different sodium silicate-to-sodium hydroxide ratio on the physical, mechanical and thermophysical properties of metakaolin geopolymers (MkGPs) was investigated. Geopolymers were prepared by activating the metakaolin with a mixture of NaOH and sodium silicate (Na2SiO3). The products obtained were characterized after 28 days of ageing. The density, porosity, compressive strength, thermal conductivity (TC), thermal diffusivity and specific heat capacity were determined. In general, the Na2SiO3/NaOH ratio has a significant effect on the compressive strength of the MkGPs. The thermal conductivity, thermal diffusivity and specific heat of MkGps measured in this work were in the range between 0.44 to 0.92 W/mK, 0.22 to 0.44 mm2/s and 1 to 3.7 MJ/m3K respectively. The highest compressive strength was 32 MPa achieved with Na2SiO3/NaOH ratio of 1.0. This mix has the best thermophysical performance due to low thermal conductivity, low thermal diffusivity and high specific heat compared to the other alkaline activator ratios. The results showed that the geopolymer is able to be used as the thermal insulating material.

Thermal Characterization of Carbon-Carbon Composites

2011 ◽  
Author(s):  
Messiha Saad ◽  
Darryl Baker ◽  
Rhys Reaves
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Critical Role ◽  
Carbon Composite ◽  
Flash Method ◽  
Carbon Composites ◽  
Energy Storage Devices ◽  
Graphitized Carbon

Thermal properties of materials such as specific heat, thermal diffusivity, and thermal conductivity are very important in the engineering design process and analysis of aerospace vehicles as well as space systems. These properties are also important in power generation, transportation, and energy storage devices including fuel cells and solar cells. Thermal conductivity plays a critical role in the performance of materials in high temperature applications. Thermal conductivity is the property that determines the working temperature levels of the material, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this research is to develop thermal properties data base for carbon-carbon and graphitized carbon-carbon composite materials. The carbon-carbon composites tested were produced by the Resin Transfer Molding (RTM) process using T300 2-D carbon fabric and Primaset PT-30 cyanate ester. The graphitized carbon-carbon composite was heat treated to 2500°C. The flash method was used to measure the thermal diffusivity of the materials; this method is based on America Society for Testing and Materials, ASTM E1461 standard. In addition, the differential scanning calorimeter was used in accordance with the ASTM E1269 standard to determine the specific heat. The thermal conductivity was determined using the measured values of their thermal diffusivity, specific heat, and the density of the materials.

scholarly journals Enhancing the mechanical properties and cytocompatibility of magnesium potassium phosphate cement by incorporating oxygen-carboxymethyl chitosan

2020 ◽  
Author(s):  
Changtian Gong ◽  
Shuo Fang ◽  
Kezhou Xia ◽  
Jingteng Chen ◽  
Liangyu Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physicochemical Properties ◽  
Bone Cement ◽  
Ph Value ◽  
Setting Time ◽  
Potassium Phosphate ◽  
Carboxymethyl Chitosan ◽  
Bioactive Substances ◽  
Magnesium Potassium Phosphate Cement

Abstract Incorporating bioactive substances into synthetic bioceramic scaffolds is challenging. In this work, oxygen-carboxymethyl chitosan (O-CMC), a natural biopolymer that is nontoxic, biodegradable and biocompatible, was introduced into magnesium potassium phosphate cement (K-struvite) to enhance its mechanical properties and cytocompatibility. This study aimed to develop O-CMC/magnesium potassium phosphate composite bone cement (OMPC), thereby combining the optimum bioactivity of O-CMC with the extraordinary self-setting properties and mechanical intensity of the K-struvite. Our results indicated that O-CMC incorporation increased the compressive strength and setting time of K-struvite and decreased its porosity and pH value. Furthermore, OMPC scaffolds remarkably improved the proliferation, adhesion and osteogenesis related differentiation of MC3T3-E1 cells. Therefore, O-CMC introduced suitable physicochemical properties to K-struvite and enhanced its cytocompatibility for use in bone regeneration.

scholarly journals A Novel Approach to Fabricate Foam Ceramics from Steel Slag

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yu Zheng ◽  
Xudong Luo ◽  
Jinlong Yang ◽  
Wenlong Huo ◽  
Chi Kang
Keyword(s):  
Compressive Strength ◽  
Ph Value ◽  
Steel Slag ◽  
Raw Material ◽  
Solid Loading ◽  
Insulation Material ◽  
Ceramic Foams ◽  
Novel Approach ◽  
The Stability ◽  
First Time

A novel approach is used for fabricating steel slag foam ceramics based on the particle-stabilized foaming method. In this work, steel slag was used as the raw material and propyl gallate (PG) was used as the surface modifier. For the first time, steel slag ceramic foams were successfully fabricated based on particle-stabilized foams. The results show that the stability of the ceramic foams was closely related to the pH value and PG concentration. The porosity and compressive strength could be controlled by changing the solid loading of steel slag and sintering temperature. The porosity of steel slag foam ceramics ranged from 85.6% to 62.53%, and the compressive strength was from 1.74 MPa to 10.42 MPa. The thermal conductivity of steel slag foam ceramics was only 0.067 W (m·K)−1, which shows that it could be used as a thermal insulation material.

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