scholarly journals Powder concretes with technogenic materials

Vestnik MGSU ◽  
2015 ◽  
pp. 101-109 ◽  
Author(s):  
Aleksandr Dmitrievich Tolstoy ◽  
Valeriy Stanislavovich Lesovik ◽  
Liliya Khasanovna Zagorodnyuk ◽  
Irina Aleksandrovna Kovaleva
Keyword(s):  
Concrete Structure ◽  
High Strength Concrete ◽  
Raw Materials ◽  
High Strength ◽  
Cement Stone ◽  
Strength Concrete ◽  
Scientists And Engineers ◽  
The Impact

Beginning with the 1970s many specialists have been dedicating their works to investigation of the possibility to use concrete modifications of non-organic materials containing amorphous silica. Almost any industrial product is beginning with raw materials obtained from the planetary interior or formed on its surface. That’s why the problem of selective choice and utilization of industrial waste is of a global character, so it is of great importance. Currently, the attention of scientists and engineers is attracted by the widespread use of high-strength concrete, different from the usual one by high content of cement stone, lesser grain size, multi-component, increased specific surface area of the filler. The performance properties of concrete to a large extent depend on the properties of aggregate and water content. It is known that empirical way to search for improving the strength of concrete has always been a laborious and time-consuming. In this regard, the actual conditions for forming a preliminary study of high-strength concrete structure have been investigated, as well as the role of processing methods in the process and nature of the impact on the quality of a concrete structure.

scholarly journals Reduce the Influence of Horizontal and Vertical Cold Joints on the Behavior of High Strength Concrete Beam Casting in Hot Weather by Using Sugar Molasses

2018 ◽  
Vol 7 (4.19) ◽  
pp. 794
Author(s):  
Fatimah Hameed Naser Al-Mamoori ◽  
Ali Hameed Naser Al-Mamoori
Keyword(s):  
High Strength Concrete ◽  
Concrete Beam ◽  
Setting Time ◽  
Weather Condition ◽  
High Strength ◽  
Point Load ◽  
Concrete Element ◽  
Strength Concrete ◽  
Hot Weather ◽  
The Impact

The current research studies the effect of cold joints on the behavior shear and flexure of High Strength Concrete (HSC) beams caused by delayed casting sequence during the hot weather in summer of Iraq.Fresh concrete should be kept alive during the various casting batches for concrete element by re-vibration. However, the over vibration caused loss in homogeneity and it is difficult to keep the workability of concrete during hot weather due to the effect of setting time.To deal with this problem of improper casting sequence, which eventually leads to the formation of cold joints, it will be used sugar waste (named as Sugar Molasses (SM)) is a by-product resulted from refining process of sugar as a delayed agent to increase the setting time in order to prevent early set of concrete due to adverse effects in construction joint of hot weather.In the current study, the first objective aims to investigate some of fresh and hardened mechanical properties of HSC (with high cement content) using SM at percentages of (0, 0.05, 0.1, 0.2, 0.3) % from the weight of cement under the concept of sustainable development. The second objective aims to investigate the location and surface texture effect of horizontal and vertical cold joints on the flexural and shear behavior of beam with/without SM. This objective includes testing of twenty four plain concrete beam of (110×110×650 mm) under two point load; half of them casting without roughing (smooth) the old layer and the other casted after roughed it.SM content of 0.2% of cement weight can improve compressive strength by about 11.2% at 28 days and delay initial setting time by about 4.617 hours (277 minutes). No adverse effect on concrete have been observed at this dosage of SM concentration for the ages of concrete cylinders studied. Delays in the setting of concrete at this dosage of SM content help in reducing the early setting of concrete and therefore reduced the impact of the cold joints formation in concrete beams under Iraqi hot weather condition. The failure load for the beams with SM of smooth and rough vertical joints is in the range between (1.95 - 2.12) and (1.46-1.37); respectively times that of the case of beam without SM. 

scholarly journals Production of Greener High-Strength Concrete Using Russian Quartz Sandstone Mine Waste Aggregates

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5575
Author(s):  
Aleksandr Tolstoy ◽  
Valery Lesovik ◽  
Roman Fediuk ◽  
Mugahed Amran ◽  
Murali Gunasekaran ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Raw Materials ◽  
Mine Waste ◽  
Natural Radionuclides ◽  
High Strength ◽  
Morphological Properties ◽  
Cement Matrix ◽  
Natural Activity ◽  
Strength Concrete ◽  
The Cost

Quartz sandstone (QS) is a mine waste; therefore, its use in construction allows for both reducing the cost of the concrete and contributing to the utilization of waste. The scientific originality of this study is the identification of models of the effect of QS aggregate on the physicomechanical, durability characteristics, and eco-safety of greener high-strength concrete. The study used an energy-efficient method of non-thermal effects of electromagnetic pulses on the destruction mechanisms of quartz-containing raw materials. The characteristics of quartzite sandstone aggregates, including the natural activity of radionuclides, were comprehensively studied. The features of concrete hardening, including the formation of an interfacial transition zone between the aggregate and the cement matrix, were studied, taking into account the chemical and morphological features of quartzite sandstone. In addition, the microstructural and morphological properties of concrete were determined after a 28 day curing. In this study, the behaviors of the concrete with QS aggregate were investigated, bearing in mind the provisions of geomimetics science on the affinity of structures. The results obtained showed that the QS aggregate had the activity of natural radionuclides 3–4 times lower compared to traditional aggregates. Efficient greener concrete with a 46.3 MPa compressive strength, water permeability grade W14, and freeze–thaw resistance of 300 cycles were also obtained, demonstrating that the performance of this greener concrete was comparable to that of traditional concrete with more expensive granite or gabbro diabase aggregates.

scholarly journals Fire Performance of Columns Made of Normal and High Strength Concrete: A Comparative Analysis

2016 ◽  
Vol 711 ◽  
pp. 564-571 ◽  
Author(s):  
Thomas Gernay
Keyword(s):  
Bearing Capacity ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Strength Loss ◽  
Fire Performance ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Strength Concrete ◽  
The Impact

The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.

Experimental Study on Impermeability and Frost Resistance of High Strength Concrete Used in Shaft of Coal Mine

2011 ◽  
Vol 287-290 ◽  
pp. 1019-1023
Author(s):  
Jing Feng Hou ◽  
Dong Ming Guo ◽  
Hui Dong Xu ◽  
Zeng Kun Yang
Keyword(s):  
Coal Mine ◽  
Frost Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Mineral Admixture ◽  
Cement Stone ◽  
Mine Shaft ◽  
Strength Concrete ◽  
Overburden Soil ◽  
Thick Overburden

This paper presents results of impermeability and frost resistance tests of a series of high strength concrete which will be used in Yuncheng coal mine shaft lining. And the shaft is one of the most difficult to construct using freezing method because of the extreme thick overburden soil. The results show the impermeability and frost resistance of the selected concrete mix proportion options can meet the special requirements of the shaft construction. It’s due to the low water-cement ratio, admixture and water-reducing agent decreases void caused by excess water. And the composite mineral admixture forms bubbles to cut off the tiny water permeable channels in cement stone. Also the filling effect and pozzolanic effect caused by fly ash contribute a lot. The research on high strength concrete used in shaft of coal mine with thick overburden soil is still rare worldwide.

scholarly journals Relations between the sensory properties and fat ingredients of lipsticks

OCL ◽  
2018 ◽  
Vol 25 (5) ◽  
pp. D502 ◽  
Author(s):  
Hélène de Clermont-Gallerande ◽  
Sarah Abidh ◽  
Alexandre Lauer ◽  
Séverine Navarro ◽  
Gérard Cuvelier ◽  
...  
Keyword(s):  
Raw Materials ◽  
Sensory Properties ◽  
Lead Times ◽  
Mechanical Resistance ◽  
Target Market ◽  
Physico Chemical ◽  
The Impact ◽  
Simplified Formula

Lipstick is a key product in the make-up sector. A woman applies lipstick to feel feminine and attractive. The sensation she perceives when she applies the product plays an important role in her attachment to her lipstick. The impact of the ingredients on the sensory properties and the quality of the lipsticks needs to be understood, so that the formulation can be more effective and the sensory properties can be precisely adjusted to the target market. During this study, multidimensional correlations were made between the percentage of ingredients, their physico-chemical specifications and the sensory properties of the raw materials on their own or the lipsticks. The objective of this study is to predict the sensory properties of lipsticks from the physico-chemical specifications of the ingredients. It is in effect quicker to access the physical data than the sensory descriptions. The lipsticks were made using a simplified formula, evaluated in a sensory analysis and their physico-chemical characteristics were measured. The relationships between the sensory properties, the ingredient specifications and their percentage of use in the formula were highlighted. The results confirm the major role of the viscosity of oils and the wax used in the formula on the sensory and mechanical properties of the lipstick. It is therefore possible to modify the sensory properties, for example to adjust the shininess of a lipstick, without altering its mechanical resistance. This opens up opportunities for developing innovative sensory textures in short lead times.

A NEW KIND OF CEMENT AS A SOLUTION TO THE ENVIRONMENTAL CHALLENGES OF MODERNITY

2021 ◽  
Author(s):  
G Kasimova
Keyword(s):  
Fly Ash ◽  
High Strength Concrete ◽  
Fresh Concrete ◽  
Raw Materials ◽  
Road Construction ◽  
High Strength ◽  
Strength Concrete ◽  
Cement Replacement ◽  
Air Content ◽  
Concrete Mix

The article presents studies on the production of high-strength concrete for road construction for a given 28-day strength on local raw materials. As a cement-replacement additive, fly ash was used. It was found out that the fresh concrete mixture had adequate workability, the air content of the concrete mix withthe sperplastifizer, the 28-day strength of the base mixture, which corresponded to the required strength.

High-Strength Concrete Structure Strengthened with CFRP: Experimental Study and Nonlinear FE Analysis

2011 ◽  
Vol 255-260 ◽  
pp. 3087-3090
Author(s):  
Hong Hai ◽  
Ying Hua Zhao ◽  
Li Ye Sun
Keyword(s):  
Experimental Study ◽  
Failure Mode ◽  
Concrete Structure ◽  
High Strength Concrete ◽  
High Strength ◽  
Fe Analysis ◽  
Fiber Reinforced ◽  
Concrete Member ◽  
Strength Concrete ◽  
Nonlinear Fe Analysis

This paper deals with high-strength concrete structure with carbon fiber reinforced plastic (CFRP) strips bonded to the shear face. The first part deals with an experimental study. The fiber reinforced plastics strengthened concrete member test presents a failure mode with debonding of the external CFRP strips from the concrete member. The second part deals with a nonlinear FE analysis with LS-DYNA . Considering of the adhesive layer, explicit finite element is used for simulating the shear failure of CFRP-strengthened concrete, obtain the whole process of structure deformation development and describe the conformation and development of crack and the failure mode. The FE results are compared with the experimental results.

scholarly journals QUALITY CONTROL AND S VALUE OF STRENGTH IN HIGH STRENGTH CONCRETE STRUCTURE USING SIMPLE ADIABATIC CURING

2002 ◽  
Vol 8 (15) ◽  
pp. 11-14
Author(s):  
Kazuhiko TATEMATSU ◽  
Junji YAMASAKI ◽  
Kin-ichi TAKAMI ◽  
Mamoru SUZUKAWA
Keyword(s):  
Quality Control ◽  
Concrete Structure ◽  
High Strength Concrete ◽  
High Strength ◽  
Strength Concrete
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