Effect of Water/Cement Ratio on the Early Age Tensile Strength of Concrete

1998 ◽  
Vol 1610 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Jon Abel ◽  
Ken Hover
Keyword(s):  
Tensile Strength ◽  
United Kingdom ◽  
Early Age ◽  
Dormant Period ◽  
Shrinkage Cracking ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Plastic Shrinkage ◽  
The United Kingdom ◽  
Time Period

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.

scholarly journals Early-Age Thermal-Shrinkage Cracking in Deep Foundations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Łukasz Grabowski ◽  
Monika Mitew-Czajewska
Keyword(s):  
Thermal Shrinkage ◽  
Future Research ◽  
Early Age ◽  
Deep Foundations ◽  
Shrinkage Cracking ◽  
The United Kingdom ◽  
Normative Requirements ◽  
Geotechnical Design ◽  
European Standards ◽  
Materials Used

Abstract With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the requirements of new constructions. While current European standards include design procedures for structural and geotechnical design, they lack provisions for massive deep foundations with regard to early-age thermal effects. This paper presents aspects of the phenomenon especially important for deep foundations and discusses normative requirements that influence their thermal behaviour. Further, the paper describes the methods and results of the research carried out in the United Kingdom on 1.50-m-thick diaphragm walls of a deep circular shaft. Shaft features are described, as well as the materials used. The measurements were carried out using vibrating wire strain gauges coupled with temperature readings. The results presented refer to one of the test panels concreted in January 2020. The temperature results are analysed together with the influence of work scheduling on the readings. Strain results that indicate contractive behaviour of the test panel are investigated together with the possible causes leading to such readings. Plans and directions for future research are discussed.

scholarly journals The Effect of Nano Metakaolin Material on Some Properties of Concrete

2013 ◽  
Vol 6 (1) ◽  
pp. 50-61
Author(s):  
Amer M. Ibrahem ◽  
Shakir A. Al-Mishhadani ◽  
Zeinab H.Naji
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Thermal Activation ◽  
Ordinary Portland Cement ◽  
Splitting Tensile Strength ◽  
Kaolin Clay ◽  
Cement Ratio ◽  
Water Cement Ratio

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.

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
Keyword(s):  
Tensile Strength ◽  
Material Properties ◽  
Bending Strength ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Suitability Assessment ◽  
Dust Treatment ◽  
Plate Plane

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.

Experimental Study on the Splitting Tensile Strength of Recycled Concrete Made of Brick and Tile

2012 ◽  
Vol 166-169 ◽  
pp. 1521-1525
Author(s):  
Hui Wang ◽  
Ai Liang Zhai
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Regression Analysis ◽  
Elastic Modulus ◽  
Splitting Tensile Strength ◽  
Recycled Concrete ◽  
Water Quantity ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Brick And Tile

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.

Organochlorine pesticide residues in human milk in the United Kingdom 1997–8

1999 ◽  
Vol 18 (10) ◽  
pp. 602-606 ◽  
Author(s):  
C A Harris ◽  
S O'Hagan ◽  
G HJ Merson
Keyword(s):  
United Kingdom ◽  
Human Milk ◽  
Organochlorine Pesticide ◽  
Pesticide Residues ◽  
Similar Time ◽  
Milk Samples ◽  
The United Kingdom ◽  
Time Period ◽  
Organochlorine Pesticide Residues ◽  
The Uk

1 The concentrations of a range of organochlorine pesticide residues have been determined in 168 samples of human milk collected between January 1997 and May 1998 in the UK. 2 Of the 18 residues sought, only p,p′-DTT, p,p′-DDE, dieldrin, HCB, β-HCH and γ-HCH were detected. 3 The continuing trend of a reduction in the concentrations of these pesticide residues in human milk samples and in the percentage of human milk samples containing residues was seen. 4 Correlations between the concentrations of p,p′-DDE, dieldrin, HCB, β-HCH and γ-HCH and age were seen. 5 When compared to studies carried out in Europe over a similar time period, residues in this present study were shown to occur at similar or lower concentrations.

scholarly journals Veterinary education in South Africa : the class of 1927 : short historical communication

2005 ◽  
Vol 76 (3) ◽  
Author(s):  
R.D. Bigalke
Keyword(s):  
South Africa ◽  
United Kingdom ◽  
Pharmaceutical Company ◽  
Private Practice ◽  
Life Histories ◽  
Male Student ◽  
Early Age ◽  
The United Kingdom ◽  
Entire Career ◽  
Veterinary Faculty

Joan Morice, a member of the class of 1927, broke the tradition of male student domination at the Onderstepoort Veterinary Faculty, but it took almost 20 years before other young ladies started following her courageous example. The accompanying photograph is unusual in the sense that the students appear in their then customary white coats instead of graduation regalia and that their dean is absent. Concise descriptions are given of the life histories of the 8 graduates. Their careers show more variation than in previous years. Only 1 of them spent his entire career at the Onderstepoort Research Institute and its Faculty, whereas another left the Institute after several years for a well-known pharmaceutical company in the United Kingdom. Although 1 entered private practice shortly after qualifying, she did not make it her permanent career and sadly died at the early age of 44. Another made the move from the field into private practice fairly late in his productive life. One left South Africa to spend most of his career in the Colonial Service in Tanganyika (now Tanzania) and later even joined the FAOin Rome. Two spent their entire careers in the field as state veterinarians - 1 died at the age of only 43 - and a third moved from the field to a locally-based pharmaceutical company.

Properties Evaluation of Repair Mortars Containing EVA and VA/VeoVa Polymer Powders

2017 ◽  
Vol 25 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
Cheng-Hao Li
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Thermal Expansion ◽  
Flexural Strength ◽  
Bond Strength ◽  
Drying Shrinkage ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Repair Materials ◽  
Repair Mortars

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.

scholarly journals Relationship between Water Cement Ratio and Characteristic Properties of Multi Walled Carbon Nano Tube Reinforced Concrete

2020 ◽  
Vol 9 (4) ◽  
pp. 231-236
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Multiwalled Carbon ◽  
Split Tensile Strength ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Concrete Mixtures ◽  
Carbon Nano Tubes ◽  
Carbon Nano Tube

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%.

scholarly journals PENGARUH LAMA PENGERINGAN BETON SERAT PANDAN PUNDAK DURI (PANDANUS TECTORIUS) TERHADAP KUAT TARIK BELAH BETON

2019 ◽  
Vol 11 (1) ◽  
pp. 1-6
Author(s):  
Faizal Hadi ◽  
Agustin Gunawan
Keyword(s):  
Tensile Strength ◽  
Strength Test ◽  
Mix Design ◽  
Normal Concrete ◽  
Split Tensile Strength ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Tensile Strength Test ◽  
Pandanus Tectorius

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) .

Development of Concrete Mix Design Nomograph Containing Polyethylene Terephtalate (PET) as Fine Aggregate

2013 ◽  
Vol 701 ◽  
pp. 12-16 ◽  
Author(s):  
Mohd Irwan Juki ◽  
Khairunnisa Muhamad ◽  
Mahamad Mohd Khairil Annas ◽  
Koh Heng Boon ◽  
Norzila Othman ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Splitting Tensile Strength ◽  
Mix Design ◽  
Fine Aggregate ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Concrete Mix Design ◽  
Mix Proportion ◽  
Concrete Mix

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.

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