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.

scholarly journals Reuse of Waste Material “Waste Sludge Water” from a Concrete Plant in Cement Composites: A Case Study

2019 ◽  
Vol 9 (21) ◽  
pp. 4519
Author(s):  
Klus ◽  
Václavík ◽  
Dvorský ◽  
Svoboda ◽  
Botula
Keyword(s):  
Cement Mortar ◽  
Fresh Concrete ◽  
Hardened Cement ◽  
Cement Composites ◽  
Complete Replacement ◽  
Economic Problems ◽  
Waste Sludge ◽  
Recycled Waste ◽  
Mixing Water

This paper presents the results of research dealing with the use of recycled waste sludge water from a concrete plant (CP) as partial or complete replacement of mixing water in cement mixtures. The need to recycle waste sludge water generated as a by-product (waste sludge water) during the production of fresh concrete in the concrete plant results from the environmental and economic problems associated with the operation of the concrete plant. Mixing water was replaced with recycled waste sludge water in the amount of 25%, 50%, 75%, and 100%. In order to determine the effect of partial or complete replacement of mixing water with waste sludge water from the concrete plant in the production of cement composites, laboratory tests of waste sludge water were carried out to determine whether the waste sludge water complies with the requirements for mixing water defined in CSN EN 1008. The tests also determined the properties of fresh cement mortar and hardened cement composites. These were tests of the beginning and end of cement mortar setting, and the strength characteristics (flexural strength, compressive strength). The results of these tests show that it is possible to replace the mixing water by waste sludge water from the concrete plant in the amount of up to 25% without significantly affecting the tested properties, in comparison with the formula containing pure mixing water.

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.

Effects of Fly Ash Addition on Compressive Strength and Flexural Strength of Foamed Cement Composites

2013 ◽  
Vol 795 ◽  
pp. 664-668 ◽  
Author(s):  
Roshasmawi Abdul Wahab ◽  
Mohd Noor Mazlee ◽  
Shamsul Baharin Jamaludin ◽  
Khairul Nizar Ismail
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Cement Composites ◽  
Volume Percent ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water To Cement Ratio

In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.

Dispersed Reinforcement Based on Natural Fibres Used in Cement Composites

2016 ◽  
Vol 722 ◽  
pp. 216-221
Author(s):  
Jitka Peterková ◽  
Martin Sedlmajer ◽  
Magdalena Kocianova
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Thermal Insulation ◽  
Considerable Effect ◽  
Fibre Reinforcement ◽  
Cement Composites ◽  
Cellulose Fibres ◽  
Natural Origin ◽  
Waste Cellulose

One of the options for improving the mechanical properties of cement composites is the use of fibre reinforcement. Nowadays, steel or polymer fibres are most frequently used for this purpose. However, given the increasingly stricter requirements related to environmental protection, one goal is to find ways of using alternative fibres of natural origin or waste fibres for which it is difficult to find other practical use. This paper focuses on one part of the development of materials which contain natural waste fibres as dispersed reinforcement in thermally insulating cement composites. The authors aimed to observe what influence the fibres have on the material’s final mechanical properties as well as thermal insulation properties. Another important factor, which was investigated, was the quotient of mechanical and thermal insulation properties. The results of this research showed that waste cellulose fibres have a considerable effect. The best compressive strength values were found in mixture M-2-BF which contained waste basalt fibres. The highest flexural strength values were reached by mixture M-3-CF-a containing cellulose fibres.

Effect of Carbon Nanotubes on Mechanical Properties of Cement Composites

2014 ◽  
Vol 915-916 ◽  
pp. 768-771
Author(s):  
Yun Feng Li ◽  
Jing Zhou ◽  
Lei Wen Gao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Brittle Failure ◽  
Cement Composites ◽  
Toughness Index ◽  
Different Content ◽  
Positive Effect

Nanotubes exhibiting great mechanical properties are expected to produce significantly stronger and tougher cement composites. The effects of Carbon Nanotubes to cement based composites are investigated in this paper. The flexural strength and the compressive strength of the CNTs cement composites under different content of are tested and the toughness indexes are analyzed. The results show that CNTs have a positive effect on the brittle failure of cement composites, and that the compressive strength and flexural strength of 0.10% CNTs cement composites are significantly increased. The toughness index of 0.05% CNTs cement composites is relatively higher.

Fine Grain Portland Cement Concrete with Complex Nanodisperse Admixture for Structure Rehabilitating

2015 ◽  
Vol 1122 ◽  
pp. 105-110
Author(s):  
Galina D. Fedorova ◽  
Gregory N. Alexandrov ◽  
Grigory I. Yakovlev ◽  
Irina S. Polyanskikh ◽  
Igor A. Pudov
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Portland Cement ◽  
Concrete Structures ◽  
Working Time ◽  
Strength Characteristics ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Fine Grain

The influence of new complex nanodisperse admixture on structure and strength characteristics of fine grain concrete used in rehabilitation of damaged concrete structures has been studied. Concrete without the admixture is more susceptible to cracking than concrete with the complex admixture, thus increasing the working time of structures. At the age of 28 days the compressive strength of fine grain concrete with the admixture reaches 52,35 MPa, the flexural strength is 5,2 MPa. The strength characteristics of concrete increased by 15%.

scholarly journals Investigations on Flexural and Compressive Strengths of Mortar Dedicated to Clinker Units—Influence of Mixing Water Content and Curing Time

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 347
Author(s):  
Jan Kubica ◽  
Iwona Galman
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Laboratory Tests ◽  
Bending Strength ◽  
Mechanical Parameters ◽  
Curing Time ◽  
The Impact ◽  
Mixing Water

The article presents laboratory tests on the impact of the mixing water content used in the preparation of fresh mortar on the flexural and compressive strength of one of the dry-mix mortars produced by a leading European producer and dedicated to bricklaying with clinker elements. The development of these parameters in relation to curing time was also analyzed. The mortar samples were prepared from a factory-made mortar mix using 4.0 L (the value recommended by the mortar manufacturer), 4.5 L, and 5 L of water per 25 kg bag of ready-made, pre-mixed dry mortar mix. All samples were tested in five series after 5, 9, 14, 21, and 28 days of sample curing. The results of these tests showed that the use of 6 and 18% more mixing water than recommended by the manufacturer (4.5 and 5 L per bag) adversely affected the basic mechanical parameters of the tested mortar. Moreover, it was found that the highest compressive strength values were obtained after 21 days of curing and not after 28 days as usual. It was also found that hardening time and higher than recommended water content adversely affected the bending strength of the mortar.

scholarly journals Properties of Pavement Quality Concrete Prepared with Recycled Coarse Aggregate

2020 ◽  
Vol 8 (5) ◽  
pp. 3186-3192 ◽  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Impact Strength ◽  
Flexural Strength ◽  
Coarse Aggregate ◽  
Strength Characteristics ◽  
Laboratory Environment ◽  
Recycled Coarse Aggregate ◽  
The Impact ◽  
Remarkable Reduction

The investigation is intended to evaluate the impact of substitution of demolished concrete debris as coarse aggregate (CA) in pavement quality concrete (PQC). The strength characteristics of PQC such as compressive strength, tensile strength, flexural strength and impact strength after adding recycled coarse aggregate (RCA) are experimentally determined in laboratory environment. Specimens of M30 grade concrete were prepared and tested. The RCA was substituted up to 50% by replacing CA content. Based on the investigation results, it was found that reduction of slump value due to the substitution of RCA in concrete. There is no remarkable reduction of compressive strength and flexural strength up to 30% and 40 % replacement of CA respectively in all the curing periods. The impact strength was reduced due to addition of RCA and observed 8% reduction after adding 20% RCA. It is suggested that RCA may be used up to 20% as CA in PQC.

The Utilization of a Combination of Recycled Rubber from Waste Tires and Waste Waters from a Concrete Plant in the Production of Cement Composites

2020 ◽  
Vol 838 ◽  
pp. 59-66
Author(s):  
Jakub Svoboda ◽  
Vojtěch Václavík ◽  
Tomáš Dvorský ◽  
Lukáš Klus ◽  
Jiří Botula
Keyword(s):  
Cement Composite ◽  
Partial Replacement ◽  
Cement Composites ◽  
Rubber Material ◽  
Waste Tires ◽  
Waste Sludge ◽  
Mortar Strength ◽  
Recycled Rubber ◽  
Mixing Water ◽  
Physical And Mechanical Characteristics

This article presents the results of a study dealing with the use of a combination of recycled rubber from waste tires as a 100% replacement of aggregate and waste sludge water from a concrete plant as a partial replacement of mixing water in the production of cement composites. The aggregate was replaced with recycled rubber material in two ratios. The first ratio was 50/50 and the other one was a 40/60 ratio of fraction 0/1 mm and fraction 1/3 mm. The mixing water was replaced with waste sludge water from a concrete plant in the amounts of 25% and 50%. The designed cement composite formulas were subjected to the test of their physical and mechanical characteristics in order to determine the properties when using a combination of recycled rubber and waste sludge water from a concrete plant. The tested properties include: consistency of the grain curve, mixing water properties, consistency of cement mortar, strength characteristics (tensile flexural strength and compressive strength). The study presents the results that are fundamentally different from the comparative samples and their use in the building industry but, at the same time, they also open up new possibilities of their use as building material.

scholarly journals WET/DRY CYCLING AND THE EFFECTS OF FIBER LOADING ON THE MECHANICAL PROPERTIES OF CEMENT COMPOSITES MIXED WITH KRAFT PULP-FIBER FROM SENGON (Falcataria Mollucana) WOOD

2018 ◽  
Vol 40 (2) ◽  
pp. 116
Author(s):  
Ismail Budiman ◽  
Widya Fatriasari
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Kraft Pulp ◽  
Volume Fraction ◽  
Pulp Fiber ◽  
Cement Composites ◽  
Water Tank ◽  
Wood Fibers ◽  
Cycling Treatment

Recently, pulp fiber-cement composites have found a practical application in the commercial market to replace hazardous asbestos fibers. For exterior applications, the effects of cyclical wetting and drying on the performance of cement composites were studied. The objective of this study was to investigate the influence of filling wood fibers in cement composites prior to and after a wet/dry cycling treatment. The testing of kraft pulp fiber filling consisted of a 3, 5, and 7% of volume fraction of the composite. The target density and water to cement ratio of the composites produced was 1.5 gcm -3 , with a 0.50 base on weight, respectively. Cement composites were formed and pressed into a mold to the targeted dimensions of 30 cm × 2.5 cm × 2.5 cm (length × width × thickness) for 24hours, before they were removed from the mold. They were then subjected into two curing system conditions. First, the boards were immersed in a water tank at 18 ± 2 °C for 28 days and then tested for their mechanical properties. Secondly, the samples were immersed in the same conditions as before, but followed by a wet/dry curing cycling for 6 times before the mechanical properties were tested. Mechanical characteristics were observed according to ASTM C293-94 for flexural strength and ASTM C116-90 for compressive strength by using a Universal Testing Machine (UTM). The addition of pulp fiber and the wet/dry cycling treatment gave a significantly linear effect on the mechanical properties of composites. The higher amount of wood fiber filling in the cement composites resulted in a lower flexural and compressive strength of the composites. Furthermore, the wet/dry cycling treatment tended to lower the flexural strength, but not the compressive strength of the composites.

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