scholarly journals Effect of Water-Cement Ratio on Pore Structure and Strength of Foam Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Zhongwei Liu ◽  
Kang Zhao ◽  
Chi Hu ◽  
Yufei Tang
Keyword(s):  
Pore Structure ◽  
Cement Paste ◽  
Water Saturation ◽  
Relative Viscosity ◽  
Foam Concrete ◽  
Analysis Software ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Image Analysis Software

Foam concrete with different dry densities (400, 500, 600, 700, and 800 kg/m3) was prepared from ordinary Portland cement (P.O.42.5R) and vegetable protein foaming agent by adjusting the water-cement ratio through the physical foaming method. The performance of the cement paste adopted, as well as the structure and distribution of air pores, was characterized by a rheometer, scanning electron microscope, vacuum water saturation instrument, and image analysis software. Effects of the water-cement ratio on the relative viscosity of the cement paste, as well as pore structure and strength of the hardened foam concrete, were discussed. Results showed that water-cement ratio can influence the size, distribution, and connectivity of pores in foam concrete. The compressive strength of the foam concrete showed an inverted V-shaped variation law with the increase in water-cement ratio.

scholarly journals Effect of Phenolic Particles on Mechanical and Thermal Conductivity of Foamed Sulphoaluminate Cement-Based Materials

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3596 ◽  
Author(s):  
Xiuzhi Zhang ◽  
Qing Yang ◽  
Qinfei Li ◽  
Heng Chen ◽  
Guofa Zheng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Pore Structure ◽  
Dry Density ◽  
Mechanical And Thermal Properties ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Performance Indexes ◽  
Foamed Concrete ◽  
Inorganic Matrix

Foamed concrete materials based on sulpoaluminate cement were prepared by the chemical foaming method. The effects of water–cement ratio, foaming agent, and foaming stabilizer on the mechanical and thermal properties of foamed concrete were studied. Meanwhile, a portion of cement was replaced with foamed phenolic particles to further optimize the performance of foamed concrete; the results show that when the water–cement ratio was 0.53, the foaming agent content was 5%, the foam stabilizer was 1%, and the substitution of phenolic particles was 20%, the performance indexes of foamed concrete were the best. Methods, describing briefly the main methods or treatments applied: dry density was 278.4 kg/m3, water absorption was 19.9%, compressive strength was 3.01 MPa, and thermal conductivity was 0.072 W/(m·K). By the pore structure analysis of the foamed concrete suing Micro-CT, it was found that when the replacement amount of phenolic particles was 20%, the pore size of foamed concrete was relatively uniform, the minimum D90 was 225 μm respectively. The combination of organic and inorganic matrix and optimized pore structure improved the performance of foamed concrete.

scholarly journals Effect of water/cement ratio on micro-nanomechanical properties of the interface between cementitious matrix and steel microfibers in ultra-high performance cementitious composites

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Vanessa Fernandes Cesari ◽  
Fernando Pelisser ◽  
Philippe Jean Paul Gleize ◽  
Milton Domingos Michel
Keyword(s):  
Transition Zone ◽  
Cement Paste ◽  
Calcium Silicate ◽  
High Performance ◽  
Calcium Silicate Hydrate ◽  
Interfacial Transition Zone ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Nanomechanical Properties ◽  
Cementitious Matrix

abstract: Ultra-high performance concretes with steel microfibers have been studied in depth with the aim of producing more efficient and durable structures. The performance of these materials depends on the characteristics of the interface between microfibers and cementitious matrix. This research investigates the micro-nanomechanical properties of the interfacial transition zone between the steel microfibers and the matrix of ultra-high performance cementitious composite. The effect of the water/cement ratio and distance from the microfiber were analyzed. The results confirm the formation of high-density calcium-silicate-hydrate (HD C-S-H) matrix at higher concentrations than low-density calcium-silicate-hydrate (LD C-S-H) for w/c ratios of 0.2 and 0.3. The properties in cementitious matrix interface with steel microfibers were very similar to that measured for the cement paste, and no significant difference was observed regarding the distance to the microfibers in relation to the elastic modulus, hardness and chemical composition. Thus, the authors can conclude that the formation of a less resistant region does not occur at the interfacial transition zone cement paste/microfibers.

Microstructure of High Strength Cement Paste Systems

1984 ◽  
Vol 42 ◽  
Author(s):  
M. Regourd
Keyword(s):  
Cement Paste ◽  
Ultrafine Particles ◽  
High Strength ◽  
Interfacial Bond ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Composite Systems ◽  
Crystalline Hydrates ◽  
Low Porosity

AbstractHigh strength cement pastes include hot pressed, autoclaved, impregnated low water/cement ratio, macrodefect free, ultrafine particles arrangement systems. The densification of the microstrucure is mainly related to a low porosity and to the formation of poorly crystalline hydrates. In composite systems like mortars and concretes, the interfacial bond between the cement paste and aggregates is moreover less porous and more finely crystallized than the normal “auréole de transition”.

Research on the Performance of Plaster Material by Chemical Foaming Method

2013 ◽  
Vol 830 ◽  
pp. 435-438
Author(s):  
Hong Xia Wang ◽  
Bo Liu ◽  
Kuang Ping Yuan ◽  
Wu Biao Duan ◽  
Fei Hua Yang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Water Temperature ◽  
Chemical Reaction ◽  
Raw Material ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Chemical Foaming

The paper introduces a kind of foaming plaster with main raw material of α- gypsum, which is produced by utilizing the chemical reaction principles H2O2 was decomposed. Meanwhile，study the changes of density，flexural strength and compressive strength of plaster material performance with the additives in different ratio. The result showed that water-cement ratio, H2O2 foaming agent and water temperature all affect the performance of the foaming plaster.

Evaluation of initial setting time due to superplasticizers

2017 ◽  
Vol 8 (2) ◽  
pp. 65
Author(s):  
Abhishek Singh ◽  
Shobha Ram ◽  
Alok Verma
Keyword(s):  
Water Content ◽  
Cement Paste ◽  
Setting Time ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Initial Setting Time ◽  
Initial Setting

This paper shows how polycarboxylate based superplasticizer affects the initial setting time of cement paste. Three superplasticizers are used in this study with different properties and aiming to determine the delay in initial setting time due to superplasticizer. Initial setting time is calculated as per IS: 4031-PART 5-1988 with different SP dosages (0.5%, 0.75%, 1.0% and 1.5% of weight of cement). Superplasticizer is an admixture which reduces the water-cement ratio or increase the workability at the same water content. This paper deals with the evaluation of initial setting time due to superplasticizers.

scholarly journals Strength and Deformability of Fiber Reinforced Cement Paste on the Basis of Basalt Fiber

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Yury Barabanshchikov ◽  
Ilya Gutskalov
Keyword(s):  
Crack Resistance ◽  
Cement Paste ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Fiber Reinforced ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Particulate Reinforcement ◽  
Reinforced Cement ◽  
Basaltic Fiber

The research object of the paper is cement paste with the particulate reinforcement of basalt fiber. Regardless of fibers’ length at the same fiber cement mix workability and cement consumption equality compressive solidity of the specimens is reduced with increasing fiber content. This is due to the necessity to increase the water-cement ratio to obtain a given workability. The flexural stability of the specimens with increasing fiber content increments in the same conditions. There is an optimum value of the fibers’ dosage. That is why stability has a maximum when crooking. The basaltic fiber particulate reinforcement usage can abruptly increase the cement paste level limiting extensibility, which is extremely important in terms of crack resistance.

Prediction of Elastic Modulus of Cement-Based Materials Based on Power’s Volume Model

2012 ◽  
Vol 253-255 ◽  
pp. 474-477 ◽  
Author(s):  
Lang Wu ◽  
Bing Yan ◽  
Bin Lei
Keyword(s):  
Elastic Modulus ◽  
Elastic Properties ◽  
Cement Paste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Micromechanics Model ◽  
Volume Model ◽  
Cement Based Materials ◽  
Hydrated Products ◽  
Multi Phase

The hydrated products, unhydrated cement and water (capillary pores) in the cement paste are seen as matrix, inclusion, Equivalent medium respectively, We used the micromechanics theories and Power’s Volume model to develop a multi-phase micromechanics model capable of simulating the elastic properties of cement-based materials, and the evolution of elastic properties in the hydration process was calculated at different water-cement ratio. The final experimental results show that this model can be used to predict the elastic properties of cement-based materials.

scholarly journals The Assessment of Strength of Cementitious Materials Impregnated Using Hydrophobic Agents Based on Near-Surface Hardness Measurements

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4583
Author(s):  
Martyna Nieświec ◽  
Łukasz Sadowski
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Concrete Structures ◽  
Surface Hardness ◽  
Cementitious Materials ◽  
Schmidt Hammer ◽  
Near Surface ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
The Impact

Recently, the surfaces of concrete structures are impregnated to protect them against the environment in order to increase their durability. It is still not known how the use of these agents affects the near-surface hardness of concrete. This is especially important for experts who use the near-surface hardness of concrete for estimating its compressive strength. The impregnation agents are colorless and, thus, without knowledge of their use, mistakes can be made when testing the surface hardness of concrete. This paper presents the results of investigations concerning the impact of impregnation on the subsurface hardness concrete measured using a Schmidt hammer. For this research, samples of cement paste with a water–cement ratio of 0.4 and 0.5 were used. The samples were impregnated with one, two, and three layers of two different agents. The first agent has been made based on silanes and siloxanes and the second agent has been made based on based on polymers. The obtained research results allow for the conclusion that impregnation affects the near-surface hardness of concrete. This research highlights the fact that a lack of knowledge about the applied impregnation of concrete when testing its near-surface hardness, which is then translated into its compressive strength, can lead to serious mistakes.

Sign in / Sign up

Export Citation Format

Share Document