Use of Separated Dust from the Formatting and Grinding Cement-Bonded Chipboards to Modify their Composition

2015 ◽  
Vol 1122 ◽  
pp. 225-228
Author(s):  
Tomáš Melichar ◽  
Dalibor Konečný ◽  
Jiří Bydžovský ◽  
Miroslav Vacula

The article presents results of the research focused on suitability assessment of separated dust from formatting and grinding of cement-bonded chipboards to modify their composition. The attention was paid to dust treatment, i.e. milling and sorting. The dust was applied to chipboards in amounts of 5 and 10%. Formulas with water-cement ratio 0.60 and 0.65 were prepared. The influence of sorted dust was subsequently evaluated using setting of selected material properties. In particular the bending strength and tensile strength perpendicular to plate plane were monitored including the influence of frost on these characteristics.

2013 ◽  
Vol 6 (1) ◽  
pp. 50-61
Author(s):  
Amer M. Ibrahem ◽  
Shakir A. Al-Mishhadani ◽  
Zeinab H.Naji

This investigation aimed to study the effect of nano metakaolin ( NMK ) on some properties (compressive strength ,splitting tensile strength & water absorption ) of concrete. The nano metakaolin (NMK) was prepared by thermal activation of kaolin clay for 2 hours at 750 Ċ. The cement used in this investigation consists of ordinary Portland cement (OPC). The OPC was partially substituted by NMK of ( 3, 5 & 10%) by weight of cement. The C45 concrete was prepared , using water/cement ratio ( W/c) of (0.53) .The Water absorption was tested at 28 days while the tests (compressive strength ,splitting tensile strength) were tested at ages of (7, 28, 60,& 90) days . The compressive strength and splitting tensile strength of concrete with NMK were higher than that of reference concrete with the same W/c ratio.The improvement in the compressive strength when using NMK was (42.2, 55.8 , 63.1% ) at age 28 days for ( 3%, 5%, &10% ) replacement of NMK respectively whereas the improvement in the splitting tensile strength was (0% , 36% & 46.8 %) at age of 28 days when using (3%, 5%, &10% ) NMK respectively. The improvement in the water absorption was (16.6%, 21.79%, &25.6 ) when using (3, 5, &10% )NMK.


2012 ◽  
Vol 166-169 ◽  
pp. 1521-1525
Author(s):  
Hui Wang ◽  
Ai Liang Zhai

By experimental, study on the elastic modulus and the splitting tensile strength together with the influence of the splitting tensile strength with different water-cement ratio, sand rate and water quantity , and the relational formula between the splitting tensile strength and the elastic modulus was summarized by regression analysis.


2017 ◽  
Vol 25 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
Cheng-Hao Li

The repair of damaged structures is a complicated problem in the construction industry and it is no uniform standard for evaluating the effectiveness of repair materials. Two different redispersible polymer powders, ethylene vinyl acetate (EVA) and polyvinyl acetate-vinyl carboxylate (VA/VeoVa), were added in the repair mortars with two water-cement ratios and three polymer-cement ratios. The effectiveness of repair materials was evaluated according to the physical, mechanical properties and micrographs. Testing program includes setting time, drying shrinkage, thermal expansion, compressive strength, tensile strength, flexural strength, bond strength, X-ray diffraction analysis, scanning electron microscopy observation. Test results show that the specimens with VA/VeoVa and w/c of 0.5 have highest compressive strength, tensile strength, flexural strength and bond strength. The specimen with EVA also has higher strength than control one at the age of 28 days. The drying shrinkage deformation of VA/VeoVa specimen is close to the control one. The specimens with VA/VeoVa have lower thermal expansion than EVA specimen when the water-cement ratio is 0.5 and there is no difference between EVA and VA/VeoVa specimens for the water-cement ratio of 0.6. The micrographs show that adding polymer powder can reduce the pore and improve the durability.


In this study effect of water-cement ratio (W/C) on the characteristic properties of multiwalled carbon nano tube reinforced concrete is analyzed. Five concrete mixtures of different water-cement ratio (W/C) with and without carbon nano tubes (CNTs) were prepared. W/C of 0.40, 0.45, 0.48, 0.50 and 0.55 were used while quantity of carbon nano tube (CNT) was fixed at 1% by weight of cement (wbc). Ratio of cement, sand and aggregates was also fixed at 1: 1.76:2.66 in all mixes. For maintaining workability 0.5% polycarboxlate based superplasticizer wbc was added in all mixes.. The workability of carbon nanotube reinforced concrete (CNTC) reduced by 60% and W/C=0.50 was found ideal for slump as well as strength. At this W/C compressive strength for CNTC increased by 7.20%, split tensile strength increased by 25.75% and flexural strength increased by 3.87%.


2019 ◽  
Vol 11 (1) ◽  
pp. 1-6
Author(s):  
Faizal Hadi ◽  
Agustin Gunawan

Concrete is a material that have the strength to compression, but it is weak against tensile strength. The weakness of the tensile strength of concrete can be minimized by adding pandanus tectorius fiber. This study was aimed to determine the effect of adding pandanus tectorius fiber to split- tensile strength of concrete and percentage of the fiber in concrete that shows the highest split- tensile strength. The specimens used in this study is cylindrical with dimensions of 30 cm in height and 15 cm in diameter (SNI 03-4810-1998). Total of specimens is 32 that consist of 8 normal concretes and 24 variation concretes. An addition of pandanus tectorius fiber with the variation of 0,25%, 0,5%, and 0,75% was based on volume of the specimen. The mix design of concrete used water-cement ratio of 0.5 and slump of 60-100 mm. The splittensile strength of concrete was tested at 7 days and 14 days of dryng after immersing for 27 days. The result of split-tensile strength test of concrete with a variation of pandanus tectorius fiber showed a decreasing. The decreasing of split-tensile strength of concrete at 41 days was smaller than at 34 days to normal concrete. The highest decreasing percentage of split-tensile strength of variation concrete to normal concrete was respectively 9,249% (variation 0,25 tested at 41 days) and 14,518% (variation 0,75% tested at 34 days) .


2021 ◽  
Vol 887 ◽  
pp. 415-421
Author(s):  
V. Ezerskiy ◽  
N.V. Kuznetsova ◽  
A.D. Seleznev

The object of study is a cement composite material with powdered utilized optical discs. The objective is to establish the dependences of the main strength characteristics – com-pressive strength, bending strength, and density – on the amount of waste added into the mix-ture and the water-cement ratio.The compositions of the mixtures for the production of the cement composite material samples consisted of the following components: cement, sand, powdered waste in the form of utilized optical discs and water.Based on the results of testing the samples, mathematical models have been developed which describe the dependences of the physical and mechanical properties of the cement com-posite material samples on the fraction of waste and water-cement ratio. It was found that with an increase in the amount of powdered waste added into the mixture, it reduces the compressive strength, bending strength, and density of the samples under study, however, the optimization of the water-cement ratio makes it possible to obtain equal strength compositions with a differ-ent fraction of waste.Component compositions of cement composite material mixtures with the addition of powdered utilized optical discs in the amount of 10 to 25 % of the total filler mass, which can provide construction products with a compressive strength class B20, are presented.


2013 ◽  
Vol 701 ◽  
pp. 12-16 ◽  
Author(s):  
Mohd Irwan Juki ◽  
Khairunnisa Muhamad ◽  
Mahamad Mohd Khairil Annas ◽  
Koh Heng Boon ◽  
Norzila Othman ◽  
...  

This paper describes the experimental investigation to develop the concrete mix design Nomograph for concrete containing PET as fine aggregate. The physical and mechanical properties were determined by using mix proportion containing 25%, 50% and 75% of PET with water cement ratio (w/c) 0.45, 0.55 and 0.65. The data obtained showed that the inclusion of PET aggregate reduce the strength performances of concrete. All the data obtained were combined into one single graph to develop a preliminary mix design nomograph for PET concrete. The nomograph consist of ; relationship between compressive strength and water cement ratio; relationship between splitting tensile strength water cement ratio; relationship between splitting tensile strength and PET percentage and relationship between compressive strength and PET percentage. The mix design nomograph can be used to assists in selecting the proper mix proportion parameters based on the criteria required.


2011 ◽  
Vol 250-253 ◽  
pp. 2167-2175 ◽  
Author(s):  
Ling Jun Xie ◽  
Ai Liang Zhai

In this paper, the splitting tensile strength experiments of recycled sintered brick-tile concrete with different water-cement ratio, sand rate and water quantity were carried out, and the change law of splitting tensile strength with above three factors was acquired and failure patterns of the samples were analyzed. The results showed that the effects of sand rate and water quantity were not clear, while water-cement ratio was relatively significant and the splitting tensile strength was inversely proportional relationship with it. And the relation between the splitting tensile strength and the cubic compressive strength was summarized from the results.


2013 ◽  
Vol 357-360 ◽  
pp. 1282-1285
Author(s):  
Hai Yong Cai ◽  
Li Bin Fu ◽  
Ling Bo Dang

Influence of replacement ratio and water-cement ratio on the recycled concrete mechanical properties were analyzed by testing the compressive strength and tensile strength of the recycled concrete. Results show that the mechanical properties of recycled concrete, compared with common concrete, can meet the requirements of the project. Water-cement ratio has great influence on compressive strength and tensile strength, replacement ratio has obvious influence on compressive strength but little on tensile.


Author(s):  
Jon Abel ◽  
Ken Hover

Following Hannant’s research in the United Kingdom, the authors measured the tensile strength of concrete between the ages of 2 and 8 hr after batching. Water/cement ratios varied from 0.3 to 0.7, and water content varied from 198.6 to 220 kg/m3 (327 to 377 lb/yd3). It appears that there is a dormant period from 2 to about 4 hr when tensile strength was immeasurably low. Pragmatically this corresponds to the time period when plastic shrinkage cracking is frequently initiated. Tensile capacity developed very rapidly after the dormant period, and in all cases development of tensile strength was more rapid the lower the water/cement ratio.


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