scholarly journals Preparation of Magnesium Phosphate Cement and Application in Concrete Repair

2018 ◽  
Vol 142 ◽  
pp. 02007 ◽  
Author(s):  
Sainan Xing ◽  
Chengyou Wu
Keyword(s):  
Magnesium Oxide ◽  
Calcination Temperature ◽  
Bonding Strength ◽  
Potassium Phosphate ◽  
Magnesium Phosphate ◽  
Dihydrogen Phosphate ◽  
Concrete Repair ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Potassium Magnesium

Potassium magnesium phosphate cement (MKPC) was prepared by using magnesium oxide (MgO) and potassium dihydrogen phosphate (KH2PO4, KDP). The effects of different calcination temperature, water-cement ratio and ratio on the operation of magnesium phosphate cement were studied. The effects of different water - cement ratio and ratio on the bonding strength of potassium magnesium phosphate cement and the application of potassium phosphate and magnesium cement in concrete repair and reinforcement were determined by experiments such as bending resistance, splitting, compression and bearing capacity. The experimental results show that the calcination temperature is 1100 °C, the calcination time is 1h, the settling time of magnesium oxide is 39min, and the compressive strength of one day reaches 53MPa. The water - cement ratio with the best bonding strength is 0.2, the mass ratio is 2:1.To meet the rapid repair of the construction requirements, is expected to be applied to the actual repair works.

scholarly journals Pore Filling Effect of Forced Carbonation Reactions Using Carbon Dioxide Nanobubbles

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4343
Author(s):  
Jihoon Kim ◽  
Ryoma Kitagaki ◽  
Heesup Choi
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Surface Modification ◽  
Calcium Carbonate ◽  
Pore Filling ◽  
Concrete Repair ◽  
Mortar Specimen ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Series Of Experiments

Various methods for repairing and modifying concrete surfaces have been proposed and applied to improve the durability of existing concrete structures. Surface modification through forced carbonation is a method of densification that forms calcium carbonate in the pores on the surface of concrete to improve its durability. In this study, to evaluate the applicability of this surface modification method to existing buildings, a series of experiments was conducted in which mortar specimens were repeatedly immersed in a carbon dioxide nanobubble aqueous solution. By evaluating the weight change and absorption rate, it was determined that the higher the water/cement ratio of the mortar specimen, the higher the pore filling effect owing to immersion in the carbon dioxide nanobubble aqueous solution. In addition, the effect of clogged pores generated by the precipitation of calcium carbonate was confirmed, and it was found that the higher the water/cement ratio of the mortar specimen, the higher the pore filling effect due to clogging. We believe that our findings contribute to the development of research and construction practices associated with concrete repair and restoration.

Study on Preparation and the Setting Time of Magnesium Phosphate Cement

2014 ◽  
Vol 1049-1050 ◽  
pp. 251-255
Author(s):  
Run Qing Liu ◽  
Ding Qiang Chen ◽  
Tian Bo Hou
Keyword(s):  
Fly Ash ◽  
Orthogonal Experiment ◽  
Setting Time ◽  
Magnesium Phosphate ◽  
Mixture Ratio ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Orthogonal Analysis ◽  
Optimal Mixture Ratio

This paper mainly researched on preparation and the setting time of Magnesium Phosphate Cement (MPC). The method of orthogonal experiment was adapted to determine the best ratio of MPC, and change the content and types of the material according to the influence of various factors, so as to get the longer setting time of MPC. The results showed that, when the water cement ratio is 0.12, the factors significantly influencing the setting time is magnesium phosphorus ratio (M/P), fly ash and borax. The optimal mixture ratio was obtained through the orthogonal analysis, namely M/P is 3/1, borax content is 16%, and the amount of fly ash is 40%. When M/P is 1/1 and 2/2, borax content is not more than 22%, and the amount of fly ash was less than 60%, the longer setting time of MPC can be produced.

scholarly journals Sintesis Kalium Magnesium Posfat Melalui Metoda Mekanokimia untuk Aplikasi sebagai Pupuk Slow Release[MECHANOCHEMICAL SYNTHESIS OF POTASSIUM MAGNESIUM PHOSPHATE FOR APPLICATION AS SLOW RELEASE FERTILIZER MATERIAL[Mechanochemical Synthesis of Potassium Magnesium Phosphate for Application as Slow Release Fertilizer Material]

Metalurgi ◽  
2017 ◽  
Vol 28 (1) ◽  
pp. 19
Author(s):  
Solihin Solihin
Keyword(s):  
Mechanochemical Synthesis ◽  
Slow Release ◽  
Potassium Phosphate ◽  
Magnesium Phosphate ◽  
Slow Release Fertilizer ◽  
Fertilizer Material ◽  
Potassium Magnesium

SINTESIS KALIUM MAGNESIUM POSFAT MELALUI METODA MEKANOKIMIA UNTUKAPLIKASI SEBAGAI PUPUK SLOW RELEASE.. Material yang bersifat slow release dapat digunakansebagai pupuk slow release, yakni jenis baru dimana pelepasan elemennya dapat diturunkan. Salah satu pupukslow release adalah potassium magnesium phosphate (KMgPO4). Analisa XRD terhadap material inimenunjukan bahwa kemurnian material ini cukup tinggi, hanya fasa KMgPO4 yang dapat dideteksi dalamsampel material ini. Analysis FTIR menunjukan bahwa teknik mekanokimia cukup berhasil untuk mensintesamaterial in. Analisa DTA menunjukan bahwa material ini stabil dari perubahan temperatur. Analisa morfologimenunjukan bahwa partikel yang tergranulasi memiliki ukuran sekitar 100 mikron. Dibanding dengan pupukbiasa yang nutriennya cepat larut, nutrien yang terlarut dari pupuk jenis slow release dapat diturunkan menjadisekitar 32-33, 22-24, and 0,1-0,7 %, untuk masing-masing potassium, phosphate and magnesium. Hasil ujileaching menunjukan bahwa material ini dapat digolongkan sebagai material yang bersifat slow release.

scholarly journals Bond between Steel Reinforcement Bars and Seawater Concrete

2020 ◽  
Vol 6 ◽  
pp. 61-68
Author(s):  
Adnan Adnan ◽  
Herman Parung ◽  
M. W. Tjaronge ◽  
Rudy Djamaluddin
Keyword(s):  
Compressive Strength ◽  
Bonding Strength ◽  
High Performance Concrete ◽  
Infrastructure Development ◽  
Normal Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Composite Cement ◽  
Steel Bar ◽  
Remote Islands

In order to promote sustainable development in the remote islands this present research attempted to study the suitability of seawater, that available abundantly surrounding the remote islands with Portland composite cement (PCC) and crushed river stones to produce concrete. This research aims to utilize seawater, and Portland composite cement (PCC) to produce high-performance concrete in order to eliminate the main problems of clean water shortage in the low land areas and the remote islands. Infrastructure development can be sustained through the effective use of natural available local materials on the remote islands. The method used in this research is an experimental method in the laboratory. Two variations of concrete were made using freshwater and seawater, respectively as a mixing material with a water to cement ratio (w/c) of 0.55. The evaluation result on concrete compressive strength and bond strength of seawater concrete were discussed. Experimental results showed the compressive strength of the seawater concrete is lower by 6.26% as compared to the normal concrete at water-cement ratio (w/c) of 0.55. In addition, the bonding strength of steel bar embedded in seawater concrete is lower by 4.34% as compared to the bonding strength of steel bar embedded in normal concrete at water-cement ratio (w/c) of 0.55. Doi: 10.28991/cej-2020-SP(EMCE)-06 Full Text: PDF

scholarly journals Use of Nondestructive Testing of Ultrasound and Artificial Neural Networks to Estimate Compressive Strength of Concrete

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 44
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
Rosely S. Cavalcanti ◽  
António C. Azevedo ◽  
Ana S. Guimarães ◽  
...  
Keyword(s):  
Neural Networks ◽  
Compressive Strength ◽  
Artificial Neural Networks ◽  
Cross Sections ◽  
Influential Factors ◽  
Average Error ◽  
Ann Model ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Artificial Neural

The work presents the results of an experimental campaign carried out on concrete elements in order to investigate the potential of using artificial neural networks (ANNs) to estimate the compressive strength based on relevant parameters, such as the water–cement ratio, aggregate–cement ratio, age of testing, and percentage cement/metakaolin ratios (5% and 10%). We prepared 162 cylindrical concrete specimens with dimensions of 10 cm in diameter and 20 cm in height and 27 prismatic specimens with cross sections measuring 25 and 50 cm in length, with 9 different concrete mixture proportions. A longitudinal transducer with a frequency of 54 kHz was used to measure the ultrasonic velocities. An ANN model was developed, different ANN configurations were tested and compared to identify the best ANN model. Using this model, it was possible to assess the contribution of each input variable to the compressive strength of the tested concretes. The results indicate an excellent performance of the ANN model developed to predict compressive strength from the input parameters studied, with an average error less than 5%. Together, the water–cement ratio and the percentage of metakaolin were shown to be the most influential factors for the compressive strength value predicted by the developed ANN model.

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