The Research of the Waste Sludge with the Content of Hazardous Substances Solidification Using Cement Matrix

2016 ◽  
Vol 865 ◽  
pp. 244-248
Author(s):  
Bozena Dohnalkova
Keyword(s):  
Compressive Strength ◽  
Hazardous Waste ◽  
Laboratory Tests ◽  
Hazardous Substances ◽  
Cement Matrix ◽  
Fly Ashes ◽  
Waste Sludge

This paper deals with the solidification/stabilization of selected type of hazardous waste with use of cementation. Different solidification formulas for this chosen waste were proposed with use of two types of cements and classic and fluid fly ashes. Then according to these formulas testing specimens were produced and after maturing process were subjected to laboratory tests - compressive strength after 28 and 60 days maturing testing and leachability testing. This paper presents results of this laboratory tests.

scholarly journals The effect of CO2 on cement composites produced with an admixture of waste sludge water from a concrete plant

2019 ◽  
Vol 14 (1) ◽  
pp. 39-46
Author(s):  
Lukas Klus ◽  
Jakub Svoboda ◽  
Vojtech Václavik ◽  
Tomas Dvorský ◽  
Jiri Botula
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Laboratory Tests ◽  
Strength Characteristics ◽  
Cement Composites ◽  
Mineralogical Analysis ◽  
Complete Replacement ◽  
Waste Sludge ◽  
Mixing Water

Abstract This article presents the results of a research dealing with the effect of CO2 on cement composites prepared on the basis of waste sludge water from the concrete plant. The designed formulas R1 and R3 use waste sludge water from the concrete plant as a partial or complete replacement of mixing water in the production of cement composites. The mixing water was replaced by waste sludge water in the amounts of 25%, 50%, 75% and 100%. Laboratory tests that are defined in ČSN EN 1008 standard were performed in order to determine the effect of partial or complete replacement of mixing water. The test specimens were further subjected to the effect of CO2 in the Lamart laboratory chamber, where the effect of CO2 was simulated for the period 50 years. Subsequently, the cement composites were tested for their strength characteristics (tensile flexural strength, compressive strength) and subjected to a mineralogical analysis. The results show that the effect of CO2 will reduce the strength characteristics of the composite compared to the comparative samples.

Durability Assessment of Cement Matrices for Neutralization Sludge Disposing

2018 ◽  
Vol 276 ◽  
pp. 282-287
Author(s):  
Bozena Dohnalkova ◽  
Rostislav Drochytka
Keyword(s):  
Compressive Strength ◽  
Hazardous Waste ◽  
Laboratory Testing ◽  
Hazardous Substances ◽  
Chemical Processing ◽  
Industrial Source ◽  
Physical Chemical ◽  
Time Period ◽  
Durability Assessment ◽  
Cement Matrices

The paper deals with durability assessment of different cement matrices for disposing of hazardous waste – neutralization sludge from physical chemical processing from an active industrial source. The durability of the matrices is estimated on the basis of laboratory testing results of compressive strength and leachability tests those indicate the possibility of matrices to bind the hazardous substances inside matrices. These tests were performed on the matrices after different time period.

scholarly journals AN EFFECTIVE WAY TO RECYCLE 3D PRINTING CONCRETE SCRAP

2021 ◽  
Vol 4 (2) ◽  
pp. 12-18
Author(s):  
D.A. Tolypin ◽  
N. Tolypina
Keyword(s):  
Compressive Strength ◽  
3D Printing ◽  
Portland Cement ◽  
Quartz Sand ◽  
Raw Materials ◽  
Electricity Consumption ◽  
Cement Matrix ◽  
Fine Aggregate ◽  
Fine Grained ◽  
Control Samples

the article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a crite-rion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the con-crete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on tra-ditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap al-lows obtaining building composites based on it with the complete exclusion of natural raw materials

Improvements on Mechanical Property and Microstructure of Cementitious Composite Incorporated with Silica Fume and Carbon Nanotube

2019 ◽  
Vol 298 ◽  
pp. 167-171
Author(s):  
Gu Yue Han ◽  
Jian Lin Luo
Keyword(s):  
Compressive Strength ◽  
Carbon Nanotube ◽  
Silica Fume ◽  
Cementitious Materials ◽  
Filler Loading ◽  
Cement Matrix ◽  
Ultrasonic Dispersion ◽  
Integrated Network ◽  
Positive Effects ◽  
Ultrafine Silica

Nano-size fillers (ultrafine silica fume (USF) or/and multi-walled carbon nanotube (MWCT)) were incorporated into cement matrix to fabricate nano-fillers reinforced cementitious materials (NFRCs) with surfactant ultrasonic dispersion and subsequently mix cast process. The flexural and compressive strengths of four groups NFRCs with varied nano-filler loading were comprehensively investigated. Results show, there are positive effects on the flexural and compressive strength of NFRCs with nano-fillers loading, especially when USF and MWCT are incorporated simultaneously, and the correspondent maximal flexural and compressive strength can increase by above 17%, 28% with respect to the baseline, respectively. The pozzolan infilling effect of USF and the crack-bridging effect of dispersed MWCT result in the dense and integrated network microstructures of cured NFRC.

scholarly journals Size Effect in Compressive Strength Tests of Cored Specimens of Lightweight Aggregate Concrete

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1187 ◽  
Author(s):  
Lucyna Domagała
Keyword(s):  
Compressive Strength ◽  
Scale Effect ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Cement Matrix ◽  
Lightweight Aggregate Concrete ◽  
Core Diameter ◽  
Aggregate Concrete ◽  
Normal Weight Concrete ◽  
Strength Tests

The aim of this paper is to discuss the unrecognized problem of the scale effect in compressive strength tests determined for cored specimens of lightweight aggregate concrete (LWAC) against the background of available data on the effect for normal-weight concrete (NWAC). The scale effect was analyzed taking into consideration the influence of slenderness (λ = 1.0, 1.5, 2.0) and diameter (d = 80, 100, 125, and 150 mm) of cored specimens, as well as the type of lightweight aggregate (expanded clay and sintered fly ash) and the type of cement matrix (w/c = 0.55 and 0.37). The analysis of the results for four lightweight aggregate concretes revealed no scale effect in compressive strength tests determined on cored specimens. Neither the slenderness, nor the core diameter seemed to affect the strength results. This fact should be explained by the considerably better structural homogeneity of the tested lightweight concretes in comparison to normal-weight ones. Nevertheless, there were clear differences between the results obtained on molded and cored specimens of the same shape and size.

Study of Correlation on Unconfined Compressive Strength between Different Soil

2013 ◽  
Vol 838-841 ◽  
pp. 926-929
Author(s):  
Xia Zhao
Keyword(s):  
Compressive Strength ◽  
Soil Moisture ◽  
Moisture Content ◽  
Unconfined Compressive Strength ◽  
Laboratory Tests ◽  
Soil Moisture Content ◽  
Correlation Coefficients ◽  
Friction Angle ◽  
Silty Clay ◽  
Soil Cohesion

Take the silty clay and clay as the research object, the correlation between bulk density, moisture content, cohesion, friction angle and unconfined compressive strength was analyzed using laboratory tests, and the results showed that soil cohesion, friction angle and unconfined compressive strength with good correlation, the correlation coefficients were all above 0.9, while severe and soil moisture content and unconfined compressive strength of correlation is weak, followed by the correlation formulas of the index and unconfined compressive strength were established, these formulas can used to predict the unconfined compressive strength of soil.

Microstructural Study of Cement Composites Produced by Hazardous Waste Stabilization/Solidification

2012 ◽  
Vol 587 ◽  
pp. 97-101
Author(s):  
Bozena Vacenovska ◽  
Rostislav Drochytka ◽  
Vit Cerný
Keyword(s):  
Fly Ash ◽  
Hazardous Waste ◽  
Cement Composite ◽  
Cement Matrix ◽  
Main Task ◽  
Cement Composites ◽  
Microstructural Study ◽  
Waste Stabilization ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

This paper deals with the chosen hazardous waste solidification/stabilisation (S/S) under the catalogue code 190811 using cement matrix with addition of classic fly ash and fluid fly ash as secondary raw binders. The main task of the research works was a microstructural study of the most successful S/S formula that will be used for development of new reclamation material. The S/S process product was subject to X-Ray analysis and to the electron microscopy analysis two years after its production to evaluate the possibility of degradation of the cement composite and releasing the contaminants into environment.

Stabilization of Marine Clay by Biomass Silica (Non-Traditional) Stabilizers

2014 ◽  
Vol 695 ◽  
pp. 93-97 ◽  
Author(s):  
Aminaton Marto ◽  
Nor Zurairahetty Mohd Yunus ◽  
Faizal Pakir ◽  
Nima Latifi ◽  
Ahmad Hakimi Mat Nor ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Laboratory Test ◽  
Unconfined Compressive Strength ◽  
Laboratory Tests ◽  
Clay Soils ◽  
Development Work ◽  
Content Increase ◽  
Marine Clay ◽  
Testing Program ◽  
Marine Clays

The presence of marine clay in Iskandar Malaysia Region, Nusajaya had caused expensive solutions in the construction of structures and roads. Alternatively, soil treatment is suggested to increase the strength of the unsuitable material to meet the constructions requirement for foundation and also to achieve the specifications for development work. In this study, a series of laboratory test has been conducted to determine the potential of Biomass Silica (BS), one of the commercial brands namely “SH-85” to stabilize marine clay to form the basis of a strong, reliable land for construction of roads and building. Testing program involves obtaining specimens of marine clays from various locations at Iskandar Malaysia Region, followed by laboratory tests to determine the Atterberg limits and Unconfined Compressive Strength (UCS) for treated and untreated of marine clay soils. The proportions of BS added were 3, 6, 9, 12 and 15% and tested at 0, 3, 7 and 28 days curing periods. The results shows that the Plasticity Index (PI) was reduce with increment of BS content. While, an addition of BS content increase in strength treated soils 60 times more than untreated soils, which is gain in early 7 curing days period. This finding indicates the BS is a suitable stabilizer for the marine clay to become strong foundation for construction of road and building.

Fabrication of Lightweight Concrete Composites Using Natural Fibers in Thailand

2018 ◽  
Vol 765 ◽  
pp. 305-308
Author(s):  
Pat Sooksaen ◽  
Vimon Boodpha ◽  
Porntipa Janrawang ◽  
Peemmawat Songkasupa
Keyword(s):  
Compressive Strength ◽  
Lightweight Concrete ◽  
Low Cost ◽  
Coal Fly Ash ◽  
Natural Fibers ◽  
Cement Matrix ◽  
Surface Adhesion ◽  
Coconut Husk ◽  
Corn Husk ◽  
Agricultural Industries

This study developed lightweight concretes by using three different natural fibers from agricultural industries in Thailand which were corn husk fiber, bagasse fiber and coconut husk fiber. Low cost lightweight concretes in this study were fabricated using Ordinary Portland Cement type-1, coal fly ash, un-treated natural fibers and NaOH-treated natural fibers. The specimens were tested for bulk density, compressive strength, microstructure and deterioration. The result showed that the strongest concrete composite was obtained using 30 vol% fine coconut husk fiber in the concrete composition. The treated fibers showed an improvement in surface adhesion between cement matrix and fibers which resulted in higher compressive strength value.

scholarly journals Fracture Behavior and Energy Analysis of 3D Concrete Mesostructure under Uniaxial Compression

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1929 ◽  
Author(s):  
Yiqun Huang ◽  
Shaowei Hu ◽  
Zi Gu ◽  
Yueyang Sun
Keyword(s):  
Compressive Strength ◽  
Fracture Behavior ◽  
Energy Analysis ◽  
Voronoi Tessellation ◽  
Fracture Pattern ◽  
Propagation Path ◽  
Cement Matrix ◽  
Cohesive Elements ◽  
Fracture Surfaces ◽  
Specimen Height

In order to investigate the fracture behavior of concrete mesostructure and reveal the inner failure mechanisms which are hard to obtain from experiments, we develop a 3D numerical model based on the Voronoi tessellation and cohesive elements. Specifically, the Voronoi tessellation is used to generate the aggregates, and the cohesive elements are applied to the interface transition zone (ITZ) and the potential fracture surfaces in the cement matrix. Meanwhile, the mechanical behavior of the fracture surfaces is described by a modified constitutive which considers the slips and friction between fracture surfaces. Through comparing with the experiments, the simulated results show that our model can accurately characterize the fracture pattern, fracture propagation path, and mechanical behaviors of concrete. In addition, we found that the friction on the loading surfaces has a significant effect on the fracture pattern and the strength of concrete. The specimens with low-friction loading surfaces are crushed into separate fragments whereas those with high-friction loading surfaces still remain relatively complete. Also, the strength of concrete decreases with the increase of the specimen height in the high friction-loading surfaces condition. Further, the energy analysis was applied to estimate the restraint impact of loading surfaces restraint on the compressive strength of concrete. It shows that the proportion of the friction work increases with the increase of the restraint degree of loading surfaces, which finally causes a higher compressive strength. Generally, based on the proposed model, we can characterize the complicated fracture behavior of concrete mesostructure, and estimate the inner fracture mode through extracting and analyzing the energies inside the cohesive elements.

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