scholarly journals Properties of Modified High Permeable Concrete with a Crumb Rubber

2019 ◽  
Vol 13 (1) ◽  
pp. 82-91 ◽  
Author(s):  
Cheng Yee Ng ◽  
Anaqi Ratna Narong ◽  
Aifaa Balqis Kamarul Zaman ◽  
Zahiraniza Mustaffa ◽  
Bashar S. Mohammed ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Void Ratio ◽  
Setting Time ◽  
Crumb Rubber ◽  
Mix Design ◽  
Tropical Region ◽  
High Porosity ◽  
The Road ◽  
Road Pavement

Background: High permeable concrete is designed with high porosity, which allows water to pass through it. By considering this ability, it has been widely used for various applications including high permeable road pavement. However, to fully adopt highly permeable road pavement technology is challenging due to high cost and maintenance, besides the present engineers and contractors have insufficient expertise and experience with this technology. Henceforth, the high porosity property is highly favorable for road curb applications especially in the tropical region like Malaysia with high rainfall intensity. Objective: This paper aimed to determine the properties of the concrete experimentally, and propose the optimum mix design of high permeable concrete for road curb. Methods: The flow value and setting time of the cement paste were investigated. Next, the effects of the modified high permeable concrete with varying amount of crumb rubber on compressive strength, permeability and void ratio were also investigated. Results and Conclusion: Results have revealed that the workability of the cement paste increases when the water-binder ratio and the amount of fly ash increase. Meanwhile, an increasing amount of cement ratio and crumb rubber lowers the flow value and consequently leads to lower void ratio and permeability. Besides, it has been found that the higher the compressive strength, the lower the void ratio and permeability of the concrete. The research findings support that using an optimum amount of cement replacement with crumb rubber as an additive may increase the performance a high permeable concrete. Herein, the results indicate that the mix design of the concrete studied has the potential to be applied onto the road curb.

scholarly journals Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1611
Author(s):  
Gintautas Skripkiūnas ◽  
Asta Kičaitė ◽  
Harald Justnes ◽  
Ina Pundienė
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Calcium Nitrate ◽  
Curing Temperature ◽  
Hardened Concrete ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

scholarly journals Effect of ultrafine natural steatite powder, super plasticizer and VMA on the fresh and hardened properties of self-compacting cement paste and mortar

2021 ◽  
Author(s):  
S. Christopher Gnanaraj ◽  
Ramesh Babu Chokkalingam ◽  
G. Lizia Thankam ◽  
S.K.M. Pothinathan
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Water Demand ◽  
Construction Material ◽  
Setting Time ◽  
Mineral Admixture ◽  
Self Healing ◽  
Chemical Admixtures ◽  
Hardened Properties ◽  
Viscosity Modifying Admixture

AbstractFor the past few decades innovation in construction material has grown a lot. This leads to special concrete such as self-compacting concrete, geopolymer concrete, self-healing concrete, etc. To prepare a special concrete apart from regular concreting material some sort of special materials was also needed, like mineral and chemical admixtures. Hence it is necessary to study the effect of these admixtures in cement paste and mortar before studying the same in concrete. Hence an attempt is made to study the effect of mineral and chemical admixtures in the fresh and hardened properties of cement paste and mortar. For this study ultrafine natural steatite powder is taken as mineral admixture and polycarboxylic based superplasticizer and glenium stream 2 were taken as chemical admixtures. Ultrafine natural steatite powder was used as additive to cement in various percentages like 0%, 5%, 10%, 15%, 20% and 25%. Superplasticizer and viscosity modifying admixture were taken as 1.5% and 0.5%, respectively. Then various combinations were worked out. To study the fresh property of cement paste consistency, initial setting time and miniature slump cone test were done based on the results yield stress of cement paste also calculated empirically. To study the hardened property compression test on cement mortar was done. Based on the test results it is clear that the addition of ultrafine natural steatite powder increases the water demand hence reduces the workability. On the other hand, it increases the compressive strength up to a certain limit. Adding superplasticizer increases the workability and reduces the water demand and viscosity modifying admixture reduces the bleeding and segregation effects hence increases the compressive strength.

scholarly journals Effect of Waste Clay Brick Powder on Physical and Mechanical Properties of Cement Paste

2021 ◽  
Vol 15 (1) ◽  
pp. 370-380
Author(s):  
David Sinkhonde ◽  
Richard Ocharo Onchiri ◽  
Walter Odhiambo Oyawa ◽  
John Nyiro Mwero
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Partial Replacement ◽  
Clay Brick ◽  
X Ray ◽  
Cement Replacement ◽  
Clay Bricks ◽  
Brick Powder ◽  
Scanning Electron

Background: Investigations on the use of waste clay brick powder in concrete have been extensively conducted, but the analysis of waste clay brick powder effects on cement paste is limited. Materials and Methods: This paper discusses the effects of waste clay brick powder on cement paste. Fragmented clay bricks were grounded in the laboratory using a ball mill and incorporated into cementitious mixes as partial replacement of Ordinary Portland Cement. Workability, consistency, setting time, density and compressive strength properties of paste mixes were investigated to better understand the impact of waste clay brick powder on the cementitious paste. Four cement replacement levels of 2.5%, 5%, 7.5% and 10% were evaluated in comparison with the control paste. The chemical and mineral compositions were evaluated using X-Ray Fluorescence and X-Ray Diffractometer, respectively. The morphology of cement and waste clay brick powder was examined using a scanning electron microscope. Results: The investigation of workability exhibited a reduction of slump attributed to the significant addition of waste clay brick powder into the cementitious mixes, and it was concluded that waste clay brick powder did not significantly influence the density of the mixes. In comparison with the control paste, increased values of consistency and setting time of cement paste containing waste clay brick powder confirmed the information available in the literature. Conclusion: Although waste clay brick powder decreased the compressive strength of cement paste, 5% partial cement replacement with waste clay brick powder was established as an optimum percentage for specimens containing waste clay brick powder following curing periods of 7 and 28 days. Findings of chemical composition, mineral composition and scanning electron microscopy of waste clay brick powder demonstrated that when finely ground, fragmented clay bricks can be used in concrete as a pozzolanic material.

scholarly journals PROPERTIES OF CEMENT PASTE AND CONCRETE CONTAINING CALCIUM CARBIDE WASTE AS ADDITIVE

2016 ◽  
Vol 36 (1) ◽  
pp. 26-31
Author(s):  
EN Ogork ◽  
TS Ibrahim
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Calcium Carbide ◽  
Linear Shrinkage ◽  
Hardened Concrete ◽  
Concrete Compressive Strength ◽  
Initial Setting Time ◽  
Standard Procedures

This paper assessed the effect of calcium carbide waste (CCW) as additive on the properties of cement paste and concrete. The CCW used was sourced from a local panel beating workshop. It was sundried and sieved through a 75 µm sieve and characterized by X-Ray Fluorescence (XRF) analytical method. The consistency, setting times and drying linear shrinkage of cement paste with CCW addition of 0, 0.25, 0.5, 0.75 and 1.0 %, respectively by weight of cement were investigated in accordance with standard procedures. The slump values of fresh concrete containing CCW as additive and of 1:2:4 mix ratio and water-cement ratio of 0.5 was determined. A total of sixty numbers of 150 mm cubes of hardened concrete were tested for compressive strength at 1, 3, 7, 28 and 56 days of curing in accordance with standard procedures. The concrete compressive strength was also modeled using Minitab statistical software based on linear regression technique. The results of the investigations showed that CCW was predominantly of calcium oxide (95.69 %) and a combined SiO2, Al2O3 and Fe2O3 content of 3.14 %. The addition of CCW in cement decreased drying shrinkage (100 %), initial setting time (78 %) and final setting time (57 %), but increased consistency (14 %) at 1.0 % CCW content. The addition of CCW in concrete also showed slight increase in slump (6.5 %) and increase in compressive strength with increase in CCW additive up to 0.5 % and decrease in compressive strength with further increase in CCW content. The 28 days compressive strength of concrete with 0.5 % CCW content was 6.4 % more than normal, while that of concrete with 1.0 % CCW content was 14.9 % less than normal. The compressive strength model of CCW-concrete was developed with R2 value of 0.830 and could be used to predict concrete compressive strength. http://dx.doi.org/10.4314/njt.v36i1.4

scholarly journals Effects of Seawater on Setting Time and Compressive Strength of Concretes with Different Richness

2021 ◽  
Vol 7 (5) ◽  
pp. 857-865
Author(s):  
Ahmed I. Ghazal ◽  
Mohammed Y. El-Sheikh ◽  
Ahmed H. Abd El-Rahim
Keyword(s):  
Compressive Strength ◽  
Beneficial Effect ◽  
Fresh Water ◽  
Cement Paste ◽  
Detrimental Effect ◽  
Tap Water ◽  
Concrete Strength ◽  
Setting Time ◽  
Strength Tests ◽  
Initial Setting

Water is one of the main constituents of concrete. Although many types of water exist, fresh water is the mostly used in concrete industry. Fresh water is expected to be in a great shortage by 2050 according to UN world water development report. Incorporating seawater in concrete mixture can help in the expected problem of scarcity of fresh water. Also, in many cases seawater may be the only available water especially in coastal regions. Many reports mention various possibilities of using seawater in concrete without detrimental effect on concrete properties. In this study another beneficial effect of seawater over tap water was concluded. Setting tests of cement paste mixed with seawater was determined using Vicat apparatus and compared to tap water. Compressive strength tests at the age of 28 days of Portland cement concretes with varied quantity of cement i.e. 300, 350, 400, 450, and 500 kg, and mixed with seawater was also performed and compared to tap water. The results show that seawater affects standard consistency of cement paste and two percent increase was required in order to attain the same consistency as tap water. It shows also seawater slightly accelerates initial setting of cement but the effect is not so pronounced so as to cause a trouble in concrete and final setting time almost remains unaltered. Compressive strength tests show an increase in concrete strength mixed with seawater for all tested mixtures and depending on quantity of cement. It also shows a beneficial effect of seawater on compressive strength of rich concrete with quantity of cement 450 and 500 kg over tap water. Doi: 10.28991/cej-2021-03091695 Full Text: PDF

scholarly journals Studi Pemanfaatan Limbah Padat Industri Pengolahan Minyak Kelapa Sawit Spent Bleaching Earth sebagai Pengganti Agregat pada Campuran Beton

2018 ◽  
Vol 15 (1) ◽  
pp. 7
Author(s):  
Denny Dermawan ◽  
Mochammad Luqman Ashari
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Palm Oil ◽  
Bleaching Earth ◽  
Setting Time ◽  
Chemical Compounds ◽  
Oil Refinery ◽  
The Other ◽  
Mix Design ◽  
Fine Aggregate

Palm oil refinery factory has solid waste by product  called Spent Bleaching Earth (SBE). SBE consists of some chemical compounds and one of them  is SiO2 up to 83,05%. SiO2 or silica fume can cause silicosis if it is exposed to the atmosphere and frequently inhaled by the workers.  On the other hand,  SiO2  is one of the material  composition of Portland cement. Thus, it is necessary to conduct a research about the utilization of SBE. as a concrete mixture. SBE is utilized as fine aggregate substitution by the composition of 0%, 10%, 20%, 30%, and 40% of the total amount of fine aggregate. The conducted tests are fineness modulus calculation, compressive strength, setting time, and TCLP. The method used for mix  design is SNI 03-2834-2000 with f’c 28,5 MPa and slump 12 ± 2 cm. This research  shows  that concretes with SBE substitution which achieve the planned compressive strength are 10% SBE with 34,16 MPa and 20% SBE with 29,06 MPa. Based on the TCLP test, the concentration of heavy metal substances in 10% SBE are below the standard. Thus, it is  scientifically proven to conclude that concrete with 10% SBE is technically proper and safe for the environment.

scholarly journals Comparison of Effects of Sodium Bicarbonate and Sodium Carbonate on the Hydration and Properties of Portland Cement Paste

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1033 ◽  
Author(s):  
Yuli Wang ◽  
Fengxia He ◽  
Junjie Wang ◽  
Qianku Hu
Keyword(s):  
Compressive Strength ◽  
Sodium Bicarbonate ◽  
Portland Cement ◽  
Cement Paste ◽  
Sodium Carbonate ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
Sprayed Concrete ◽  
Final Setting Time ◽  
Portland Cement Paste

Carbonates and bicarbonates are two groups of accelerators which can be used in sprayed concrete. In this study, the effects of the two accelerators sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) (0%, 1%, 2%, 3%, and 4% by weight of ordinary Portland cement OPC) on the properties of OPC paste were compared. The results show that both of them could accelerate the initial and final setting time of OPC paste, but the effect of the two accelerators on the compressive strength were different. After 1 day, sodium bicarbonate at 3% had the highest strength while sodium carbonate at 1% had the highest strength. After 7 days, both of the two accelerators at 1% had the highest compressive strength. After 28 days, the compressive strength decreased with the increase of the two. The improved strength at 1 and 7 days was caused by the accelerated formation of ettringite and the formation of CaCO3 through the reactions between the two with portlandite. The decrease of strength was caused by the Na+ could reduce the adhesion between C-S-H gel by replacing the Ca2+. NaHCO3 was found be a better accelerator than Na2CO3.

scholarly journals Preparation and Performance of a New-Type Alkali-Free Liquid Accelerator for Shotcrete

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Yanping Sheng ◽  
Bin Xue ◽  
Haibin Li ◽  
Yunyan Qiao ◽  
Huaxin Chen ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Cement Mortar ◽  
Retention Rate ◽  
Setting Time ◽  
Test Results ◽  
Initial Setting Time ◽  
Initial Setting ◽  
New Type ◽  
And Performance

A new type of alkali-free liquid accelerator for shotcrete was prepared. Specifically, the setting time and strength and shrinkage performance of two kinds of Portland cement with the accelerator were fully investigated. Moreover, the accelerating mechanism of alkali-free liquid accelerator and the hydration process of the shotcrete with accelerator were explored. Results show that alkali-free liquid accelerator significantly shortened the setting time of cement paste, where the initial setting time of cement paste with 8 wt% of the accelerator was about 3 min and the final setting time was about 7 min. Compressive strength at 1 day of cement mortar with the accelerator could reach 23.4 MPa, which increased by 36.2% compared to the strength of cement mortar without the accelerator, and the retention rate of 28-day compressive strength reached 110%. In addition, the accelerator still shows a good accelerating effect under low temperature conditions. However, the shrinkage rate of the concrete increased with the amount of the accelerator. 5~8% content of accelerator is recommended for shotcrete in practice. XRD and SEM test results showed that the alkali-free liquid accelerator promoted the formation of ettringite crystals due to the increase of Al3+ and SO42- concentration.

Using High Temperature for Improve Compressive Strength of Ordinary Portland Cement Paste (OPC) – A New Approach

2014 ◽  
Vol 894 ◽  
pp. 70-76
Author(s):  
Abdoullah Namdar ◽  
Fadzil Mat Yahaya ◽  
Mashita Mohd Yusoff
Keyword(s):  
Surface Roughness ◽  
Compressive Strength ◽  
Portland Cement ◽  
Cement Paste ◽  
Ordinary Portland Cement ◽  
Setting Time ◽  
New Approach ◽  
Force Microscopy ◽  
Atomic Force ◽  
Portland Cement Paste

Cement paste was replaced with kaolin-bentonite. The specimens were exposed to elevated temperature for 3 hours in a ceramic furnace and cooled down to room temperature. After cooling, the effect of kaolin-bentonite (particles sized of < 45μm) on hydration, rehydration, surface roughness and compressive strength of ordinary Portland cement (OPC) paste were investigated. Atomic Force Microscopy (AFM) was used to study surface roughness of OPC paste-additive mixture. The application of fire on OPC paste was analyzed. The results showed imposed heat (500 oC for 3 hours) accelerates the hydration process of OPC, and reduces setting time. Increased heat to 1000 oC, leads to zero compressive strength of specimens, the compressive strength of OPC continuously reduces after specimen has fully cooled down. A method for recovery of compressive strength of OPC after offing fire has been suggested. The method of offing fire has important effects on the compressive strength of concrete. The best results for specimen content are cement-kaolin-bentonite paste, exposure to 500 o C, after 90 days of curing, and cooling down in water. In this case the compressive strength has been increased around 60 % compared to not using additive and not exposing to heat.

Study on the Early Hydration of Cement Paste Containing Sodium Chloride

2014 ◽  
Vol 621 ◽  
pp. 35-38 ◽  
Author(s):  
Rahimah Embong ◽  
Andri Kusbiantoro
Keyword(s):  
Compressive Strength ◽  
Sodium Chloride ◽  
Cement Paste ◽  
Setting Time ◽  
Chloride Ion ◽  
Strength Development ◽  
Early Hydration ◽  
Initial Setting Time ◽  
Additive Component ◽  
Initial Setting

This paper studies the effect of sodium chloride as the additive component in cement paste. Sodium chloride was included at 0.5%, 1%, 1.5%, and 2% by weight of cement content. Analysis on the performance of this reagent was conducted via setting time, compressive strength, and porosity test. Based on the setting time analysis, the inclusion of sodium chloride can extend the initial setting time of cement paste up to 24.91% longer than control specimen. Obstruction on the formation of calcium silicate hydrate gel by sodium and chloride ion was one of the possible causes to this phenomenon. Acceleration on the compressive strength development by sodium chloride was also detected. It appears that sodium chloride was able to de-flocculate the coagulated cement particles and reduced the viscosities of cement slurries; hence resulted in faster early hydration process.

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