An Accurate and Quick Measuring Method for Mix Proportion of Concrete Paste in Construction Site

2010 ◽  
Vol 450 ◽  
pp. 482-485
Author(s):  
Li Peng Cai ◽  
Ii Young Jang ◽  
Ying Wei Yun ◽  
Seong Kyum Kim
Keyword(s):  
Setting Time ◽  
Measuring Method ◽  
In Situ Monitoring ◽  
Construction Site ◽  
Monitoring Method ◽  
Initial Setting Time ◽  
Mix Proportion ◽  
Initial Setting

An effective in-situ monitoring method for MPCP is urgently needed in civil engineering field. In this research, a quick and accurate in-situ measuring method for mix proportion of concrete is put forward. This method can succeed in measuring real mix proportion of any concrete paste precisely within 20 minutes according to four parameters of concrete before initial setting time of concrete. By comparing the designed mix proportion of concrete with the real measured one in construction site by this method, the quality of concrete can be demonstrated. This method can evaluate the reliability of mix proportion for real concrete in construction site quickly and precisely, and ensure the quality of concrete structures to avoid the occurrence of engineering accidents.

Online Prediction and Verification of Cured Quality of Advanced Composites in Autoclave Process

2016 ◽  
Vol 703 ◽  
pp. 3-10
Author(s):  
Yong An Zhang ◽  
Li Hua Zhan
Keyword(s):  
In Situ Monitoring ◽  
Metallographic Analysis ◽  
Resin Flow ◽  
Composite Part ◽  
Monitoring Method ◽  
Verification Method ◽  
Part Quality ◽  
Ultrasonic Phased Array

The strain in curing process of composite part would be influenced by curing compaction, resin flow, curing action and tool-part interaction, meanwhile these factors would also influence the final cured quality of composite part. In this paper, FBG(fiber Bragg grating) sensors are used to in-situ monitoring the strain of composite parts, which are cured in four different pressure situation by autoclave: 0.0Mpa,0.2Mpa,0.4Mpa,0.6MPa. by analyzing the strain change rule, the part quality is predicted, then the predictive result is compared with some verification method: measurement of part’s boundary dimension, ultrasonic phased array scanning, metallographic analysis. The result shows that, the prediction is consistent with verification, the in-situ monitoring method by using FBG sensor is available for predicting cured quality of composite parts accurately: increase curing pressure is benefit of part compaction, resin flow, and reduce delamination,pores in composite part, finally improving the part quality dramatically.

scholarly journals Investigation on the Compressive Strength and Time of Setting of Low-Calcium Fly Ash Geopolymer Paste Using Response Surface Methodology

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3461
Author(s):  
Pauline Rose J. Quiatchon ◽  
Ithan Jessemar Rebato Dollente ◽  
Anabel Balderama Abulencia ◽  
Roneh Glenn De Guzman Libre ◽  
Ma. Beatrice Diño Villoria ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Setting Time ◽  
Initial Setting Time ◽  
Alkali Activator ◽  
Setting Times ◽  
Confirmatory Tests ◽  
Initial Setting

Approximately 2.78 Mt of coal fly ash is produced in the Philippines, with a low utilization rate. Using fly ash-based geopolymer for construction will lessen the load sent to landfills and will result in lower GHG emissions compared to OPC. It is necessary to characterize the fly ash and optimize the geopolymer components to determine if it can replace OPC for in situ applications. The activator-to-precursor ratio, the water-to-solids ratio, and the sodium hydroxide-to-sodium silicate ratio were optimized using a randomized I-optimal design from the experimental results of 21 runs with five replicates, for a total of 105 specimens of 50 mm × 50 mm × 50 mm paste cubes. The engineering properties chosen as the optimization responses were the unconfined compressive strength (UCS), the initial setting time, and the final setting time. The samples were also ambient-cured with the outdoor temperature ranging from 30 °C to 35 °C and relative humidity of 50% ± 10% to simulate the on-site environment. Runs with high unconfined compressive strength (UCS) and short setting times were observed to have a low water-to-solids (W/S) ratio. All runs with a UCS greater than 20 MPa had a W/S ratio of 0.2, and the runs with the lowest UCS had a W/S of 0.4. The initial setting time for design mixes with a W/S ratio of 0.2 ranged from 8 to 105 min. Meanwhile, five out of seven design mixes with a W/S ratio of 0.4 took longer than 1440 min to set. Specimens with an alkali activator ratio (NaOH/WG) of 0.5 (1:2) and 0.4 (1:2.5) also had significantly lower setting times than those with an alkali activator ratio of 1. The RSM model was verified through confirmatory tests. The results of the confirmatory tests are agreeable, with deviations from the expected UCS ranging from 0 to 38.12%. The generated model is a reliable reference to estimate the UCS and setting time of low-calcium FA geopolymer paste for in situ applications.

scholarly journals Effects of Soluble Lignocellulose Substances of Wood Particles on the Mechanical Properties of Lightweight Concrete

2018 ◽  
Vol 7 (4.20) ◽  
pp. 377
Author(s):  
Aqil M. ALmusawi ◽  
Zaid A. ALzaidi ◽  
Tamara A. Qasim
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Lightweight Concrete ◽  
Setting Time ◽  
Treated Wood ◽  
Boiling Water ◽  
Initial Setting Time ◽  
Mix Proportion ◽  
Wood Particles ◽  
Initial Setting

Recent trends in lightweight concrete manufacturing have led to a proliferation of studies demonstrating that wood aggregates can be used to produce sustainable green concrete composites. However, wood particles contain soluble substances (saccharides), which have a significant effect on the setting time of Portland cement. To attain a better understanding of this, two types of wood were treated in boiling water. After the treatment process, the resulting water (“boiling water of wood”) was used to study its effect on the initial setting time of Portland cement. The mechanical properties and the density were also investigated for concrete mixtures consisting of 0, 5, 7.5, and 10% treated wood particles (weight replacement from coarse aggregate). As a result, the effect of the wood’s soluble substances was determined and the optimum mix proportion was chosen for achieving the minimum nominal density and the best mechanical properties.  

Effect of Additions on Properties of the Mullite-Based Investment Materials

2011 ◽  
Vol 467-469 ◽  
pp. 934-939
Author(s):  
Gui Lin Yu ◽  
Nan Li ◽  
You Sheng Li ◽  
Yi Ning Wang
Keyword(s):  
Compressive Strength ◽  
Silica Gel ◽  
Compression Strength ◽  
Setting Time ◽  
Initial Setting Time ◽  
Initial Setting ◽  
The Relationship

Additives will affect directly the clinic operational properties of investment materials, and finally affect the quality of castings. The relationship between additions and properties of the mullite-based investments has been studied. This paper describes effect of HBO3, Na5P3O10 and (NaPO3)6 on properties (including fluidity, initial setting time and compressive strength) of the mullite-based investment materials.It is found that with addition of HBO3, the fluidity of the mullite-based investment materials improves greatly, the initial setting time prolongs, and the compressive strength of investment materials changes little；with addition of Na5P3O10, the fluidity of mullite-based investments improves greatly, the compression strength increases, and the amount of silica gel decreases clearly；with addition of (NaPO3)5, the fluidity of mullite-based investments increases, the initial setting time prolongs, the compression strength decreases, and the amount of silica gel decreases clearly.

scholarly journals Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1611
Author(s):  
Gintautas Skripkiūnas ◽  
Asta Kičaitė ◽  
Harald Justnes ◽  
Ina Pundienė
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Calcium Nitrate ◽  
Curing Temperature ◽  
Hardened Concrete ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

scholarly journals Non-Dispersive Anti-Washout Grout Design Based on Geotechnical Experimentation for Application in Subsidence-Prone Underwater Karstic Formations

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1587
Author(s):  
Khaqan Baluch ◽  
Sher Q Baluch ◽  
Hyung-Sik Yang ◽  
Jung-Gyu Kim ◽  
Jong-Gwan Kim ◽  
...  
Keyword(s):  
Fractured Rock ◽  
Setting Time ◽  
Visual Assessment ◽  
Initial Setting Time ◽  
Permeable Sediments ◽  
Coarse Aggregates ◽  
Saturated Rock ◽  
Initial Setting ◽  
Level 3 ◽  
Grey Relational

A new non-dispersive, anti-washout grout consisting of ordinary Portland cement, slag, superplasticizer, and methylbenzyl cellulose is proposed herein for the treatment of open karst, jointed and fractured rock, open-work gravel, and permeable sediments. A series of laboratory experiments were performed to design an anti-wash out grout suitable for grout injection of coarse aggregates depicting partially and open-jointed saturated rock mass and grouting concrete aggregates for underwater construction. The Taguchi orthogonal array was used to obtain nine different grout mix ratios. A total of four variables were considered, each with three different levels of the water–cement ratio, slag, and dosage of additives such as the superplasticizer and methyl benzyl cellulose. The laboratory determination of grout characteristics recording of mini slump, temperature, pH, visual assessment of grout dispersion, bleeding, and initial setting time and as well as uniaxial compressive strengths and permeabilities of the hardened grout samples were tested. To evaluate the suitability of the grout mixes, an analysis of variance was used for factor analysis and Grey relational analysis (GRA) was used to determine the optimal grout mix design. Based on the GRA, the following levels of the factors afforded the best results: water level 1 (0.3%), SP level 3 (0.01%), methylbenzyl cellulose level 2 (0.002%), and slag level 3 (0.1%). This paper describes the research methodology, detailed research observations, and analyses involved in designing the appropriate concrete mix. Based on the conclusions, relevant commendations regarding the suitability of grout testing equipment and grout mix designs are presented.

Nanostructure Growth Supported by In Situ RHEED Evaluation

2017 ◽  
Vol 885 ◽  
pp. 234-238
Author(s):  
Péter Kucsera ◽  
Tamás Sándor ◽  
Gusztáv Varga Tényi ◽  
Márton Csutorás ◽  
Gergely Bátori ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
In Situ Monitoring ◽  
Nanostructure Formation

The in-situ monitoring of the MBE grown nanostructures can be carried out using the RHEED method. During the droplet epitaxal growth, the observation of the nanostructure formation is very important to understand the growth kinetics. In the present work, a novel in-situ RHEED evaluation and further MBE related developments are introduced, with which the quality of the nanostructure preparation can be improved.

scholarly journals Stability Assessment of Mining Excavations: the Impact of Large Depths

2018 ◽  
Vol 40 (3) ◽  
pp. 180-187
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Łukasz Bednarek
Keyword(s):  
Rock Mass ◽  
In Situ Monitoring ◽  
Stability Assessment ◽  
Underground Excavations ◽  
Deformation Prediction ◽  
Large Depth ◽  
Coal Deposits ◽  
The Impact

AbstractBack in the early 1980s, coal deposits occurring at depths of ~700 m below surface were already regarded as large-depth deposits. Meanwhile, today the borderline depth of large-depth mining has extended to >1,000 m. Design, excavation and maintenance of mining roadways at the depth of >1,000 m have, therefore, become crucial issues in a practical perspective in recent years. Hence, it is now extremely important to intensify research studies on the influence of large depths on the behaviour of rock mass and deformation of support in underground excavations. The paper presents the results of the study carried out in five mining excavations at depths ranging from 950 to 1,290 m, where monitoring stations with measurement equipment were built. The analysis of data from laboratory and coal mine tests, as well as in situ monitoring, helped to formulate a set of criteria for stability assessment of underground excavations situated at large depths. The proposed methodology of load and deformation prediction in support systems of the excavations unaffected by exploitation is based on the criteria referring to the depth of excavation and the quality of rock mass. The depth parameter is determined by checking whether the analysed excavation lies below the critical depth, whereas the rock mass quality is determined on the basis of the roof lithology index (WL) and the crack intensity factor (n)

scholarly journals Aplikasi Response Surface Methodology pada Optimasi Penambahan Blast Furnace Slag Terhadap Waktu Pengikatan dan Kuat Tekan Semen

2020 ◽  
Vol 4 (1) ◽  
pp. 61
Author(s):  
Hardjono Hardjono ◽  
Cucuk Evi Lusiani ◽  
Agung Ari Wibowo ◽  
Mochammad Agung Indra Iswara
Keyword(s):  
Compressive Strength ◽  
Response Surface Methodology ◽  
Blast Furnace ◽  
Response Surface ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Central Composite ◽  
Furnace Slag

Produksi semen setengah jadi (clinker) membutuhkan energi yang tinggi sehingga menggunakan batu bara dalam jumlah besar. Hal ini menyebabkan biaya produksi dari pabrik semen juga tinggi. Kebutuhan energi yang besar untuk menghasilkan clinker tersebut dapat dikurangi dengan menambahan blast furnace slag sebagai campuran pembuatan semen. Campuran clinker dapat menghasilkan produk semen yang memiliki waktu pengikatan dan kuat tekan sesuai SNI. Pengaruh penambahan blast furnace slag sebagai campuran clinker terhadap waktu pengikatan dan kuat tekan semen dapat dioptimalkan dengan response surface methodology (RSM) menggunakan Central Composite Design (CCD). Optimasi dengan menggunakan RSM bertujuan untuk mengetahui kondisi optimum pada penambahan blast furnace slag dan clinker terhadap variabel respon berupa waktu pengikatan awal, waktu pengikatan akhir, dan kuat tekan. Hasil uji ANOVA dan analisis response surface menunjukkan bahwa penambahan blast furnace slag sebagai campuran dalam pembuatan semen memberikan pengaruh yang signifikan terhadap waktu pengikatan awal, waktu pengikatan akhir, dan kuat tekan. Penambahan 5% blast furnace slag dengan 92,5% clinker pada campuran clinker dan gypsum merupakan kondisi optimum yang memberikan pengaruh signifikan terhadap variabel respon.The production of clinker consumes high energy and causes high production cost of cement industry. It can be reduced by adding blast furnace slag as a mixture in cement production. The blast furnace slag - clinker mixture can produce cement with setting time and compressive strength according to SNI. The effect of the addition of blast furnace slag as a clinker mixture to the setting time and compressive strength of cement can be optimized by response surface methodology (RSM) using Central Composite Design (CCD). Optimization by using RSM aims to determine the optimum condition of the blast furnace slag – clinker mixture to the initial setting time, final setting time, and compressive strength. ANOVA test results and response surface analysis show that the addition of blast furnace slag into the cement mixture has a significant influence on the initial setting time, final setting time, and compressive strength. The addition of  5% blast furnace slag with  92.5% clinker in the mixture of clinker and gypsum is the optimum condition which gives a significant effect on the response variable.

scholarly journals Properties of non-standard fly ash – slag cements containing calcareous fly ash

2013 ◽  
Vol 12 (3) ◽  
pp. 215-222
Author(s):  
Katarzyna Synowiec
Keyword(s):  
Fly Ash ◽  
Blast Furnace Slag ◽  
Strength Class ◽  
Setting Time ◽  
Heat Of Hydration ◽  
Initial Setting Time ◽  
Granulated Blast Furnace Slag ◽  
Unfavorable Effect ◽  
Initial Setting ◽  
Furnace Slag

The paper presents the tests results of the properties of non - standard fly ash - slag cements composition. Both natural (unprocessed) and activated by grinding calcareous fly ash was used. It was found that the calcareous fly ash next to the granulated blast furnace slag may be a component of low - clinker cements (ca. 40%). Those cements are characterized by low heat of hydration and overdue of initial setting time in comparison with Ordinary Portland Cement, moreover they have an unfavorable effect on consistency and its upkeep in time. Production of fly ash - slag cements is possible for strength class 32,5 N when the component of cement is raw fly ash, and for strength classes 32,5 N, 32,5 R and 42,5 N when ground fly ash was used. Fly ash activated by grinding was characterized by higher activity.

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