scholarly journals Research on C30 Concrete Mix Proportion in Guangdong Province

2020 ◽  
Vol 213 ◽  
pp. 02039
Author(s):  
Guangxing Lai ◽  
Jianli Yin ◽  
Junhui Ye ◽  
Yujia Chen ◽  
Wei Xiao
Keyword(s):  
Guangdong Province ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Bleeding Rate ◽  
Slag Powder ◽  
Mix Proportion ◽  
Concrete Mix ◽  
Water Test ◽  
The Difference ◽  
Bleeding Water

The reasons of C30 concrete bleeding in winter in Guangdong province were studied by collecting the concrete mix proportions of C30 concrete mixing plants in Guangdong, Fujian, Henan, Hunan, Chongqing and Shaanxi regions, the difference between the concrete mix proportions in Guangdong and other regions was investigated. Based on the representative concrete mix proportion in Guangdong province, the concrete bleeding water test was carried out, and the correlation between the amount of different cementing materials and the bleeding rate was investigated. The results showed that compared with other regions, the C30 concrete mix proportion in Guangdong has the lowest total cementitious material, which made it more prone to bleeding. The amount of slag powder and the total amount of cementitious materials have a high correlation with the bleeding rate. With the increase of the amount of slag powder and the total amount of cementitious materials, the bleeding rate decreases.

scholarly journals Influence of Dimethacrylate Monomer on the Polymerization Efficacy of Resin-Based Dental Cements—FTIR Analysis

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 247
Author(s):  
Aleksandra Maletin ◽  
Ivan Ristic ◽  
Tanja Veljovic ◽  
Bojana Ramic ◽  
Tatjana Puskar ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Clinical Practice ◽  
Chemical Structure ◽  
Cementitious Materials ◽  
Degree Of Polymerization ◽  
Cementitious Material ◽  
Ftir Analysis ◽  
Dental Cement ◽  
Polymerization Mechanism ◽  
The Difference

The degree of polymerization for dimethacrylate resin-based materials (BisGMA, TEGDMA, UDMA, HEMA) ranges from 55 to 75%. Literature data indicate that polymerization efficacy depends, among other factors, on the type of methacrylate resin comprising the material. The aim of this study was to evaluate the polymerization efficacy of four dental cement materials characterized by different polymerization mechanisms using FTIR analysis. In the present study, the FTIR method was adopted to analyze the degree of polymerization efficacy of four resin-based dental cement materials, two of which were self-cured and two were dual-cured cements. The IR spectral analysis was performed 24 h after the polymerization of the cementitious material. RelyX ARC cement exhibits the lowest polymerization efficacy (61.3%), while that of Variolink II (85.8%) and Maxcem Elite is the highest (90.1%). Although the efficacy of self-cured cements appears to be superior, the difference is not statistically significant (p = 0.280). Polymerization efficacy largely depends on the chemical structure of the material in terms of the presence of a particular methacrylate resin and less on the polymerization mechanism itself, i.e., whether it is a self-cured or dually cured dental cement. Thus, in clinical practice, cementitious materials with a higher proportion of TEGDMA compared with BisGMA are recommended.

COMPARATIVE INVESTIGATION OF STRENGTH PROPERTIES OF CONCRETE MIXED WITH VARIOUS POWDER AS ALTERNATIVE CEMENTITIOUS MATERIALS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Isamu Yoshitake ◽  
Keisuke Miyamoto ◽  
Jun Mizushima ◽  
Kurumi Yamamoto ◽  
Koichiro Yamato
Keyword(s):  
Concrete Strength ◽  
Cementitious Materials ◽  
Comparative Investigation ◽  
Strength Properties ◽  
Cementitious Material ◽  
Limestone Powder ◽  
Mineral Admixtures ◽  
Powder Materials ◽  
Slag Powder ◽  
Chloride Resistance

Mineral admixtures are often mixed in concrete as an alternative cementitious material. The use of powder materials indirectly contributes to mitigation of environmental impact caused from Portland cement production which is a major source of CO2 emission. Furthermore, some of powder can improve properties of fresh and hardened concretes. A huge number of reports examining effects of admixture have been published in the world. However, it is not easy to compare the effect of admixture under a certain test condition. The present study aims to examining strength properties of concrete incorporating various admixtures. All admixtures tested herein were mixed in concrete as an alternative cementitious material, and the cement replacement ratios were in the range of 0.2 to 0.6. The tested powder materials are limestone powder, fly-ash, blast furnace slag powder, silica-fume, and inorganic admixture which was recently developed to increase chloride resistance. The focus of the study is to quantify the effect of these admixture on concrete strength. The paper reports compressive, split tensile and flexural strengths of these concretes, and discusses the effect of powder materials.

Effects of Packing Degree and Calcium-Silicon Ratio of Cementitious Material on Strength of Reactive Powder Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1034-1037
Author(s):  
Tao Ji ◽  
Bao Chun Chen ◽  
Yi Zhou Zhuang ◽  
Zhi Bin Huang ◽  
Yong Ning Liang
Keyword(s):  
Silicon Dioxide ◽  
Cementitious Materials ◽  
Strength Test ◽  
Cementitious Material ◽  
Molar Ratio ◽  
Reactive Powder Concrete ◽  
Mix Proportion ◽  
Study Results ◽  
Calcium Silicon ◽  
Reactive Powder

Aim & Goff model was used to predict the packing degree of cementitious materials including cement and silica fume. The mix proportions of reactive powder concrete (RPC) with different packing degree and calcium-silicon ratio of cementitious materials were designed and a strength test was carried out. The study results reveal that the flexural strength and compressive strength of RPC are related to the packing degree and calcium-silicon ratio of cementitious materials. For the mix proportion of RPC with the calcium- silicon molar ratio of 1.353 that is slightly less than the theoretical value of 1.42, where calcium hydroxide can react with silicon dioxide more fully, its strength of RPC approaches summit although its packing degree of cementitious material is not the largest one.

scholarly journals Development of Fly Ash Composite Binder and Optimization of Slurry Ratio

2021 ◽  
Author(s):  
Qingfeng Zhuo ◽  
Lei Ba ◽  
Jing Wang ◽  
Qifeng Wang
Keyword(s):  
Fly Ash ◽  
Mass Fraction ◽  
Cementitious Materials ◽  
Physicochemical Analysis ◽  
Ratio Test ◽  
Composite Binder ◽  
Bleeding Rate ◽  
Slag Powder ◽  
Body Strength ◽  
Cemented Backfill

In view of the high cost of cement filling, the new cementitious materials are developed by using solid waste resources. Firstly, on the basis of material physicochemical analysis, the fly ash composite cementation ratio test and optimization test are carried out to determine the optimal ratio. Then, the filling body strength and pipeline transportation characteristics test are carried out to analyze they influence law. Finally, the genetic algorithm is used to optimize the slurry ratio. The results show that the strength of cemented backfill increases linearly with the increase of slurry concentration; The slump and bleeding rate of slurry decrease with the increase of slurry mass fraction, and increase with the decrease of binder sand ratio, the optimal proportion of fly ash (FA) based composite binder is w(FA): w(clinker): w (desulfurized gypsum (DG)): w (slag powder (SP)) =40:12:12:36; The optimum slurry ratio is 1:4 of binder/sand and 72% of concentration.

Design Method of Fly Ash Concrete Mix Proportion Based on Stable Paste-Aggregate Ratio

2012 ◽  
Vol 490-495 ◽  
pp. 2110-2114
Author(s):  
Qing Wei Sun ◽  
Han Zhu
Keyword(s):  
Fly Ash ◽  
Design Method ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Fly Ash Concrete ◽  
Mix Proportion ◽  
Absolute Volume ◽  
Concrete Mix ◽  
Binder Ratio ◽  
Current Design

According to problems with the paste to aggregate ratio increases significantly and lack of recognition to cementitious materials effect of fly ash in current design method of fly ash concrete mix proportion, the paper introduces a new design method of fly ash concrete mix proportion that completely bases on the stable paste to aggregate ratio. The thoughts of parts of cement replaced by equal fly ash or by excessive fly ash in traditional method are not used in this method that starting from the stable paste to aggregate ratio directly, and using the connections of water-binder ratio and concrete strength to deduce the calculation formula of fly ash concrete mix proportion with method of absolute volume. The paper sums up the calculation steps of this new method, and combines with an example to verify the feasibility and effectiveness of this method.

STRENGTH PROPERTIES OF DURABLE CONCRETE MADE WITH VARIOUS ALTERNATIVE CEMENTITIOUS MATERIALS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Isamu Yoshitake ◽  
Shun Inoue ◽  
Keisuke Miyamoto ◽  
Koichiro Yamato
Keyword(s):  
Cementitious Materials ◽  
Strength Properties ◽  
Cementitious Material ◽  
Limestone Powder ◽  
Replacement Ratio ◽  
Cement Replacement ◽  
Fundamental Properties ◽  
Slag Powder ◽  
Chloride Attack ◽  
Efficiency Factors

Many researchers investigated various concrete made with the cementitious materials, hence the effects of various admixture are well known. Most researches focused on an alternative cementitious material, tested concrete properties by varying the cement-replacement ratio. The optimum cement-replacement ratio may be different by each admixture. The present study examined the strength properties of concrete incorporating various admixtures. The cementitious materials tested in this study were fly-ash, blast furnace slag powder, silica-fume, limestone powder, and an artificial admixture which has high resistance to chloride attack. First, fundamental properties of the concrete incorporating the admixture were summarized referring to previous durability tests. Second, the strength properties of concrete made with some cement-replacement ratios by the cementitious materials were examined. In addition, alternative cement efficiency factors (k) of each cementitious material were estimated.

scholarly journals Coupled Preparation of Ferronickel and Cementitious Material from Laterite Nickel Ores

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4992
Author(s):  
Ruimeng Shi ◽  
Xiaoming Li ◽  
Yaru Cui ◽  
Junxue Zhao ◽  
Chong Zou ◽  
...  
Keyword(s):  
Direct Reduction ◽  
Cementitious Materials ◽  
Tricalcium Silicate ◽  
Cementitious Material ◽  
Raw Material ◽  
Tricalcium Aluminate ◽  
Thermodynamic Conditions ◽  
Nickel Ores ◽  
Main Components ◽  
Factsage Software

Nickel slags can be produced through ferronickel preparation by the pyrometallurgical processing of laterite nickel ores; however, such techniques are underutilized at present, and serious environmental problems arise from the stockpiling of such nickel ores. In this study, a modification to the process of ferronickel preparation by the direct reduction of carbon bases in laterite nickel ores is proposed. The gangue from the ore is used as a raw material to prepare a cementitious material, with the main components of tricalcium silicate and tricalcium aluminate. By using FactSage software, thermodynamic calculations are performed to analyze the reduction of nickel and iron and the effect of reduction on the formation of tricalcium silicate and tricalcium aluminate. The feasibility of a coupled process to prepare ferronickel and cementitious materials by the direct reduction of laterite nickel ore and gangue calcination, respectively, is discussed under varying thermodynamic conditions. Different warming strategies are applied to experimentally verify the coupled reactions. The coupled preparation of ferronickel and cementitious materials with calcium silicate and calcium aluminate as the main phases in the same experimental process is realized.

STUDIES ON HABITUATION TO COLD PAIN

1966 ◽  
Vol 44 (2) ◽  
pp. 287-293 ◽  
Author(s):  
Jacques LeBlanc ◽  
Pierre Potvin
Keyword(s):  
Cold Water ◽  
Mental Arithmetic ◽  
Blood Pressure Response ◽  
Human Subjects ◽  
Cold Pain ◽  
Left Hand ◽  
Water Test ◽  
The Difference ◽  
The Right ◽  
Habituation To Cold

It was possible to produce habituation to cold in a group of human subjects by immersing the left hand in cold water for [Formula: see text] minutes twice a day for 19 days. The right hand did not adapt. Another group of subjects was exposed similarly with the difference that an anxiety test (mental arithmetic test) was always given simultaneously with the cold-water test. In this second group the original blood pressure response, i.e. for the first day, was greater than in the first group because of the cumulative effects of the two tests. After 19 days definite evidence was obtained for adaptation to these two tests administered together. However, when these tests were given separately to the second group, no adaptation was evident; adaptation occurred only to both tests given simultaneously. These results indicate that no adaptation develops to cold per se if the subjects are distracted from cold discomfort. It was also found that adaptation of one hand to cold water not only failed to induce adaptation in the opposite hand but even reinforced responses of the unadapted hand. These findings suggest a participation of the central nervous system in adaptation to cold pain, and tend to minimize the importance of local peripheral changes.

The Properties of Flue Gas Desulphurization (FGD) Gypsum

2011 ◽  
Vol 105-107 ◽  
pp. 2204-2208 ◽  
Author(s):  
Run Xia Hao ◽  
Xiao Yan Guo
Keyword(s):  
Mechanical Properties ◽  
Flue Gas ◽  
Steel Slag ◽  
Optical Microscope ◽  
Cementitious Material ◽  
Fgd Gypsum ◽  
Technical Performance ◽  
Slag Powder ◽  
Steel Slag Powder ◽  
Flue Gas Desulphurization

The properties of flue gas desulphurization (FGD) gypsum were analysized by Thermo-gravimetry/differential scanning calorimetry (TG/DSC), technical performance analysis, optical microscope and Scanning electron microscope (SEM). Mechanical properties of FGD gypsum-steel slag powder cementitious material were researched. The results revealed that FGD gypsum have similar moisture content, major component CaSO4·2H2O with natural gypsum, and has better technical performance than natural gypsum. The results of optical microscope and SEM of the FGD gypsum hydration support this further. When the dosage of steel slag powder is 15%, containing activator ,better mechanical properties can be obtained. Key words: FGD gypsum, Property, Cementitious material

Experimental Research on Peridotite Concrete for Neutron Shielding

2013 ◽  
Vol 423-426 ◽  
pp. 1031-1035
Author(s):  
Jin Jun Wang ◽  
Guo Feng Li ◽  
De Chuan Meng
Keyword(s):  
Neutron Shielding ◽  
Crystal Water ◽  
Concrete Aggregates ◽  
Mix Proportion ◽  
Concrete Mix ◽  
Energy Neutron ◽  
Transmission Data ◽  
Shielding Material ◽  
Different Thickness ◽  
Thermal Stability Of

Peridotite containing high crystal water is used as concrete aggregates in this research. The mineral composition and thermal stability of peridotite are experimentally analyzed, and the concrete mix proportion design is optimized. The neutron shielding performance of peridotite concrete specimens are tested using 241Am-Be neutron source. The transmission data of different thickness and different energy neutron are calculated. It concludes that peridotite concrete has a good performance in neutron shielding and peridotite is an excellent neutron shielding material.

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