scholarly journals Study of Concrete Strain for T-Beams Retrofitting by Poly-Urethane-Cement Material (PUC)

2013 ◽  
Vol 5 (7) ◽  
pp. 2354-2359 ◽  
Author(s):  
Haleem K. Hussain ◽  
Lian Zhen Zhang ◽  
Gui Wei Liu
Keyword(s):  
Cement Material ◽  
Concrete Strain

A Comprehensive Study of Osteogenic Calcium Phosphate Silicate Cement: Material Characterization and In Vitro/In Vivo Testing

2015 ◽  
Vol 5 (4) ◽  
pp. 457-466 ◽  
Author(s):  
Tianxing Gong ◽  
Zhiqin Wang ◽  
Yixi Zhang ◽  
Yubiao Zhang ◽  
Mingxiao Hou ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Material Characterization ◽  
Cement Material ◽  
Phosphate Silicate ◽  
In Vivo Testing ◽  
Comprehensive Study

scholarly journals MICROSCOPIC FEATURES OF CEMENT PASTE MODIFIED BY FINE PERLITE

2016 ◽  
Vol 7 ◽  
pp. 12
Author(s):  
Vladimír Hrbek ◽  
Veronika Koudelková ◽  
Pavel Padevět ◽  
Petr Šašek
Keyword(s):  
Electron Microscopy ◽  
Construction Industry ◽  
Lightweight Aggregate ◽  
Cement Matrix ◽  
Instrumented Indentation ◽  
Cement Sample ◽  
Cement Material ◽  
Material Development ◽  
Microscopic Features ◽  
Cement Binder

The use of waste material and replacement of binder element in cementitious composites is in focus of material development. Perlite in the construction industry is usually used in form of lightweight aggregate enhancing the insulating performance of concrete. This paper focuses on integration of fine perlite into the cement matrix and possible replacement of the cement binder in the composition of the material. The macromechanical performance of the modified paste is tested on specimens with 5, 10, 15 and 20% fine perlite substitution and pure cement sample. To distinguish the effect of the perlite on the microstructural level, pure cement material and specimen containing 10% of fine perlite are investigated by the electron microscopy. Furthermore, the mechanical properties of individual phases are examined and compared on same samples by instrumented indentation. The presented results enabled estimation of fine perlite impact on the macro and microscopic performance of the material.

scholarly journals MAIN PROBLEMS OF MANUFACTURING ASPHALT CONCRETE MIXTURES IN LITHUANIA/ASFALTBETONIO MIŠINIŲ GAMYBOS SVARBIAUSIOS PROBLEMOS LIETUVOJE

2000 ◽  
Vol 6 (1) ◽  
pp. 39-45
Author(s):  
Donatas Čygas
Keyword(s):  
Asphalt Concrete ◽  
High Speed ◽  
Statistical Data ◽  
Concrete Mixture ◽  
Cement Material ◽  
Asphalt Cement ◽  
Concrete Mixtures ◽  
Concrete Quality ◽  
Regressive Analysis ◽  
Speed Gradient

The article describes the main problems of manufacturing asphalt concrete mixtures at the factories under Ministry of Communication in the Republic of Lithuania. The Lithuanian Road Network is up to 21.122 km of state roads. 1.455 km of them are motorways, 3.415 km—national roads and 16.251 km—regional roads. Half of the state roads in Lithuania are paved with asphalt concrete. 98% of the motorways and 36% of the regional roads have asphalt pavement. Asphalt concrete pavement resistance to corrosion can be increased by improving asphalt concrete mixture production technology: ie by updating technological equipment, changing technological conditions and developing new methods of asphalt concrete mixture production. Therefore, the updating of asphalt concrete mixture production technologies is a very important factor for improving road operating properties and ensuring proper duration of asphalt concrete pavements. Here is the essence of the new separate successive technology: crushed stone and sand are mixed with bitumen in the main asphalt concrete mixer, the amount of bitumen being calculated according to the bitumen absorption in the materials. Then the asphalt cement material produced in a separate high-speed mixer is passed, and the whole mixture is remixed in the main mixer and supplied to the customer. Both separate consequent technologies differ from each other in the order of supplying asphalt cement material into the main mixing unit. Separate successive technology was theoretically grounded by the correlation between the technological thickness of bituminous film and the chemical-mineralogical composition and size of constituents, by the correlation between the particle size and their capability to compose aggregates, by the emergence of the oriented binding material coating on the technological bituminous film encoating mineral particles. Special attention is given to the manufacturing of asphalt cement material in a separate high-speed mixer (3 Table). It was theoretically grounded that mineral filler passing through the intensive shift zone between the paddle ends of the high-speed mixer and the walls of mixing chamber disintegrate and new active surfaces become visible. The molecular structure changes and free radicals appear. This intensive mixing guarantees high bitumen adsorption on the surface of mineral filler, which increases asphalt concrete resistance to corrosion and its durability, improves ecological environment in the asphalt concrete plant. In order to confirm the reliability of research results and explain correlative and regressive regularity, statistical data were processed applying statistical data processing programming system “STATGRAPHICS”. The linear regressive analysis for determining close relations of separate asphalt concrete quality indicators with speed gradient of asphalt cement material shift in a high-speed mixer was performed. Therefore, the possibility to change shift speed gradient from 3000 to 5000 1/s is provided in terms of reference for manufacturing asphalt concrete mixing plant. Correlation between separate asphalt concrete quality indicators and asphalt cement material shift speed gradient as well as bitumen amount in the asphalt cement material was determined by multi-dimensional regressive analysis of experimental data. The calculated correlation factor squared (R2) and F criteria indicate the adequacy and reliability of the multidimensional regression model.

scholarly journals Mechanical Strengths of Sawdust-Ash-Admixed Gum Arabic Concrete

2021 ◽  
Vol 8 (1) ◽  
pp. 12-29
Author(s):  
Augustine Uchechukwu Elinwa
Keyword(s):  
Cement Content ◽  
Gum Arabic ◽  
Strength Ratio ◽  
Design Strength ◽  
Conventional Concrete ◽  
Cement Material ◽  
Cement Ratio ◽  
Setting Times ◽  
Concrete Mixtures ◽  
Mechanical Strengths

Gum Arabic and sawdust ash were used both as an emulsifier admixture and supplementary cement material to address some of the gaps between pozzolanic and conventional concretes. Four concrete mixtures of 1: 2.24: 2.71, with a water-cement ratio of 0.5, and cement content of 370 kg/m3, was used. The concrete mixtures were designated as M-00, M-00GA, M-10GAS, and M-30GAS, signifying the control, control with gum Arabic (GA), and mix with both gum Arabic and sawdust ash (GAS), respectively. The dosage was 0.5 % of GA and the SDA replacement by wt. % was at 10 % and 30 %, respectively. The concrete samples were cured for 90 days, and tested for mechanical strengths. The results showed that adding GA alone to concrete mixture improved the mechanical strengths of the concrete and the gum Arabic acted like an accelerator. When both GA and SDA were used together in the dosage of 0.5 % with 10 % and 30 % proportions respectively, the mechanical strengths of the concrete decreased. The findings also reported that the two-third strength ratio at 28-days of curing which is used for the conventional concrete in stripping the formwork, may not be appropriate for use on pozzolanic concrete. This is because of the delay in setting times and thus, attaining the required design strength. Therefore, it is proposed to be taken at an age beyond 28 days of curing to carter for the pozzolanic effects which starts well above 28-days.

scholarly journals Utilization of Plastic Waste Polyethylene Terephthalate (Pet) as a Coarse Aggregate Alternative in Paving Block

2019 ◽  
Vol 280 ◽  
pp. 04007
Author(s):  
Wiku A. Krasna ◽  
Rijali Noor ◽  
Denny D. Ramadani
Keyword(s):  
Coarse Aggregate ◽  
Hydraulic Press ◽  
Plastic Waste ◽  
Fine Aggregate ◽  
Pet Waste ◽  
Cement Material ◽  
Weight Measurement ◽  
Plastic Wastes ◽  
Waste Polyethylene

PET plastic waste is found everywhere in Banjarbaru City compared to other plastic wastes. It is an excellent prospect to reuse the PET plastic waste. The demand of mountain rock and stone from natural resources increases as happened in Aranio Sub District, Banjar Regency. This research is expected to find one way of suppressing the growth of the number of stone mines or natural stone. Based on SNI 03-0691-1996, the classification of the paving block differentiated according to its usage class, one of which is the C quality used by pedestrians. PET waste used as a coarse aggregate previously processed into aggregate with the ratio of cement material, fine aggregate, a coarse aggregate of 1:6:4. PET waste is processed by melting PET and forming into aggregates. The paving with PET waste process by a hydraulic press machine and tested for strength after 28 days. The result of weight measurement with the specimen increases the amount of PET in the paving block mixture, the paving weight decreases as well as the compressive strength.

scholarly journals Experimental Study on Mechanical and Functional Properties of Reduced Graphene Oxide/Cement Composites

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3015 ◽  
Author(s):  
Ning Zhang ◽  
Wei She ◽  
Fengyin Du ◽  
Kaili Xu
Keyword(s):  
Graphene Oxide ◽  
Electric Conductivity ◽  
Reduced Graphene Oxide ◽  
Cement Composite ◽  
Cementitious Material ◽  
Cement Composites ◽  
Morphological Effect ◽  
Cement Material ◽  
Reduced Graphene ◽  
Electric Shielding

This study develops a novel self-sensing cement composite by simply mixing reduced graphene oxide (rGO) in cementitious material. The experimental results indicate that, owing to the excellent dispersion method, the nucleation and two-dimensional morphological effect of rGO optimizes the microstructure inside cement-based material. This would increase the electric conductivity, thermal property and self-induction system of cement material, making it much easier for cementitious material to better warn about impending damage. The use of rGO can improve the electric conductivity and electric shielding property of rGO-paste by 23% and 45%. The remarkable enhancement was that the voltage change rate of 1.00 wt.%-rGO paste under six-cycle loads increased from 4% to 12.6%, with strain sensitivity up to 363.10, without compromising the mechanical properties. The maximum compressive strength of the rGO-mortar can be increased from 55 MPa to 71 MPa. In conclusion, the research findings provide an effective strategy to functionalize cement materials by mixing rGO and to achieve the stronger electric shielding property and higher-pressure sensitivity of rGO–cement composites, leading to the development of a novel high strength self-sensing cement material with a flexural strength up to 49%.

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