Influence of cement paste matrix properties on the autogenous curing of high-performance concrete

2004 ◽  
Vol 26 (5) ◽  
pp. 499-507 ◽  
Author(s):  
Semion Zhutovsky ◽  
Konstantin Kovler ◽  
Arnon Bentur
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Matrix Properties

Influence of Lightweight Aggregate on Durability of High Performance Concrete

2009 ◽  
Vol 405-406 ◽  
pp. 197-203
Author(s):  
Bao Sheng Zhang ◽  
Li Juan Kong ◽  
Yong Ge
Keyword(s):  
Pore Structure ◽  
Cement Paste ◽  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Bound Water ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete

High performance concrete (HPC) with a water/cement ratio (w/c) of 0.32 and different lightweight aggregate (LWA) contents (0%, 25%, 50%, 75%, 100%) were prepared, and the influence of LWA on concrete frost-resistance and impermeability at different ages were studied, as well as the hydration degree, hydrated product, pattern and pore structure of the paste around aggregate. The results show that, by replacing normal weight aggregate (NWA) with 50% and 100% volume contents of pre-wetted LWA respectively, the chemical bound water of the cement paste surrounding aggregate are increased 12.1% and 22.7% as compared to concrete mixed without LWA. And at 28 days, lightweight aggregate concrete has the highest Ca(OH)2 content, whereas the 90-day Ca(OH)2 content of normal weight concrete is the highest. This proves that, with the increase of LWA content in concrete, both of the internal curing effect of pre-wetted LWA and secondary hydration effect of fly ash (FA) are strengthened, this can also be verified by the SEM study. Furthermore, the pore structure of the cement paste around aggregate can be improved consequently. The performance of frost-resistance of HPC can be improved by mixing LWA, the 90 day-frost-resistance of lightweight aggregate concrete is about 2.5 times of that of concrete mixed without LWA. The influence of LWA on the impermeability of HPC is different from normal concrete. When LWA content is more than 50%, the HPC impermeability decreased obviously, however at later age the difference between them becomes minor.

The Mechanism of Mineral Admixture in Cement Hydration

2012 ◽  
Vol 450-451 ◽  
pp. 1528-1531
Author(s):  
Mei Li Zhao
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
Cement Hydration ◽  
High Performance Concrete ◽  
Cement Mortar ◽  
Sem Analysis ◽  
Mineral Admixture ◽  
Hydration Mechanism ◽  
Curing Period ◽  
Durability Performance

The mineral admixture is one of the indispensable materials for ordinary high-performance concrete. In this paper, the pure cement paste and cement paste replacing by mineral admixture were tested by cement mortar. The SEM analysis of pure cement paste and mineral admixture paste after curing period of 7 days and 28 days.From the picture of SEM after the period of 7 days and 28 days,the cement hydration mechanism was suspected.It could be used for explanating the physical performance and durability performance of the high perfromance concrete with mineral admixture.

Comparative Study on the Application of Naphthalene Water-Reducing Agent and Polycarboxylate Water-Reducing Agent in High-Performance Concrete

2011 ◽  
Vol 217-218 ◽  
pp. 522-526 ◽  
Author(s):  
Lin Gao ◽  
Yan Shi ◽  
Guo Qiang Xu
Keyword(s):  
Growth Rate ◽  
Comparative Study ◽  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Cement Mortar ◽  
Reducing Agent

We respectively conduct performance contrast test on cement paste, cement mortar, and high-performance concrete which have been added naphthalene water-reducing agent and polycarboxylate water-reducing agent. Studies show that naphthalene water-reducing agent can better improve the performance of concrete and increase the fluidity of concrete to ensure its keeping slump. Meanwhile, the age strength and the growth rate of strength of concrete with mixing polycarboxylate water-reducing agent has been significantly improved than those of naphthalene water-reducing agent, which can better meet the strength requirements of concrete and get a bright application prospect that naphthalene water-reducing agent can not reach.

scholarly journals Effect of quartz powder and mineral admixtures on the properties of high-performance concrete

Vestnik MGSU ◽  
2019 ◽  
pp. 102-117 ◽  
Author(s):  
Duc Vinh Quang Nguyen ◽  
Olga V. Aleksandrova ◽  
Yuriy M. Bazhenov
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Mineral Admixtures ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Quartz Powder ◽  
Additional Reduction

Introduction. This study focuses on the use of silica fume partially replacing cement with 0, 5, 7.5, 10, 12.5 and 30 % constant replacement of fly ash by weight of cement in concrete. Concrete is probably the most extensively used construction material in the world. But the conventional concrete is losing its uses with time and high-performance concrete (HPC) is taking that place. HPC has superior mechanical properties and durability to normal strength concrete. Because of, the microstructure of HPC is more homogeneous than that of normal concrete (NC) due to the physical and chemical contribution of the mineral admixtures as well as it is less porous due to reduced w/c ratio with the addition of a superplasticizer. The inclusion of additives helped in improving the properties of concrete mixes due to the additional reduction in porosity of cement paste and improving the particle packing in the interfacial transition zone (between cement paste and the aggregates).In this experimental investigation the behavior of HPC with silica fume and fly ash with and without quartz powder were studied. The water-binder ratio was kept 0.3 and 20 % quartz flour as partial replacement of fine aggregate for all cases. Materials and methods. Used materials in Vietnam, as follow, Sulfate-resisting Portland cement - PCSR40 (type V) of company Luks Cement (Vietnam) Limited was used in the work. Crushed granite of fraction 9.5…20 mm - as coarse aggregate, Natural sand from Huong river of 0.15…2.5 mm fraction with the fineness modulus of about 3.0 and quartz powder with an average particle size of 5…10 μm were used as fillers; Sika® Viscocrete®-151 is a superplasticizer based on a blend of 3rd generation PCE polymers was used as a plasticizing admixture. The flg ash from Pha Lai thermal power plant and Sika silica Sikacrete® PP1 (particle size < 0.1 μm) was used as a mineral active admixture. The study of strength and technological properties of high-performance concrete was performed by using standard methods. Results. Established by icate that, the workability and strength increase at a certain level and after that, they decline with further increase in the replacement level of silica fume is 12.5 %, on the basis of 30 % FA replacement, the incorporation of 10 % SF showed equivalent or higher mechanical properties and durability compared to the reference samples. Conclusions. HPC consists of mineral admixtures such as silica fume and fly ash use combine quartz powder and superplasticizer helped in improving the strength and durability of concrete mixes due to the additional reduction in porosity of cement paste and an improved interface between it and the aggregate. With 30 % fly ash is optimum dosage used to replacement of cement, incorporation 10 % SF (by weight) and combine of partial replacement of fine aggregate by 20 % quartz powder. On the other hand, a few mathematical equations can be used to derive the durability properties of concrete based on its compressive strength.

Numerical Simulation of Autogenous Shrinkage in High-Performance Cement Paste Based on a Multi-Component Hydration Model

2008 ◽  
Vol 385-387 ◽  
pp. 629-632
Author(s):  
Seung Min Lim ◽  
Han Seung Lee ◽  
Xiao Yong Wang
Keyword(s):  
Numerical Simulation ◽  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Autogenous Shrinkage ◽  
Curing Temperature ◽  
Hydration Process ◽  
Material System ◽  
Water Mixture ◽  
Hydration Model

Autogenous shrinkage is the term for the bulk deformation of a closed, isothermal, cement-based material system not subjected to external forces. It is associated with the internal volume reduction of cement/water mixture in the course of the hydration process. However, addition of blended components to cement, especially such as fly ash or silica fume, for the high-performance concrete will lead to a densification of the microstructure. The autogenous shrinkage deformation will increase and the following autogenous shrinkage crack will do harm to durability of concrete structure. In this paper, numerical simulation is suggested to predict autogenous shrinkage of high performance cement paste. The simulation is originated from a multicomponent hydration model. The numerical program considers the influence of water to cement ratio, curing temperature, particle size distribution, cement mineral components on hydration process and autogenous shrinkage. The prediction result agrees well with experiment result.

Improving Packing Density of Powder in Cement Paste for Production of High-Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1640-1647 ◽  
Author(s):  
Albert K.H. Kwan ◽  
J. J. Chen ◽  
Wilson W. S. Fung ◽  
Leo G. Li
Keyword(s):  
Silica Fume ◽  
Cement Paste ◽  
Packing Density ◽  
High Performance ◽  
High Performance Concrete ◽  
Great Influence ◽  
Ratio Increase ◽  
Excess Water ◽  
Packing Method ◽  
Condensed Silica Fume

The packing density of the powder in cement paste has great influence on the performance of the concrete. A higher packing density could at the same water/powder ratio increase the amount of excess water for lubricating the cement paste and thereby improve the flowability of the concrete. Alternatively, it would allow the water/powder ratio to be reduced to improve the strength of the concrete without compromising the flowability. Therefore, it is of great interest, especially for production of high-performance concrete, to maximize the packing density of the powder. This study aims to investigate the roles of superplasticizer and fillers in the packing density of the powder in cement paste. Packing density tests were carried out to determine the packing density of cement with various dosages of superplasticizer and different fillers (limestone fine, superfine cement and condensed silica fume) added using a newly developed wet packing method. The results showed that the addition of superplasticizer can significantly improve the packing density of cement while the addition of fillers can further improve the packing density of the powder.

Effect of Metakaolin on the Physical Properties and Setting Time of High Performance Concrete

2013 ◽  
Vol 539 ◽  
pp. 195-199
Author(s):  
Bao Min Wang ◽  
Hai Nan Ma ◽  
Ming Li ◽  
Yu Han
Keyword(s):  
Physical Properties ◽  
Constant Temperature ◽  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Setting Time ◽  
Cementitious Material ◽  
Test Results ◽  
Slump Flow ◽  
Static Flow

Abstract. Kaolin native to Jilin Province was calcined at the constant temperature of 750°C for 4 hours to obtain the high pozzolanic metakaolin(Al2Si2O7). The effects of metakaolin (MK) on the static flow expansion of cement paste and the workability and setting time of concrete were studied with the content of 0, 5%, 10% and 15% by weight of cementitious material. The test results show that: when the dosage of superplasticizer is 2% by weight of cementitious material, the setting time of concrete shortens obviously and the slump and expansion decrease with the raising of MK content. When 5% of cement is replaced by MK, the setting time of concrete shortens by 5%; the slump and the slump flow decrease by 5.5% and 4.4% respectively.

scholarly journals Effect of the cement paste volume on the consistency of mixes for high performance massive and self-compacting concretes

2015 ◽  
Vol 14 (2) ◽  
pp. 123-130
Author(s):  
Bartłomiej Zarzycki ◽  
Wojciech Piasta
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Strength Test ◽  
Self Compacting Concrete ◽  
Flow Table ◽  
Compressive Strength Test ◽  
Concrete Mix ◽  
High Influence

The article presents the results of research concerning the influence of the volume of cement paste and the w/c ratio on the consistency of concrete mixes for high-performance massive and self-compacting concrete. The research covered six types of concrete mixes containing from 220 to 420 dm3 of cement paste in a cubic meter. Three of them were designed as high-performance concrete and for comparison three conventional ones. The consistency was tested with two methods: concrete slump test and flow table test, also additional tests of self-compacting mix were made. Compressive strength test were conducted to prove that concretes are high-performance. A high influence of the volume of cement paste on the workability and consistency of fresh concrete mix has been found, while the influence of the w/c ratio is considerably lower due to the dosage of high-quality superplasticizer.

Morphology and Strength of Cement Paste from Clay as Nanomaterial

2014 ◽  
Vol 490-491 ◽  
pp. 19-24 ◽  
Author(s):  
M.S. Muhd Norhasri ◽  
M.S. Hamidah ◽  
A. Mohd Fadzil
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
High Performance Concrete ◽  
Human Life ◽  
Sol Gel ◽  
Hydration Product ◽  
Strength Properties ◽  
Cement Matrix ◽  
The Matrix ◽  
Early Strength

Now days the application of nanomaterials was vastly growing in the development of new material to improve the quality of human life. Particles of nanomaterials which are in nanoscale helps to improve to the characteristics of the existing micro based materials. The application of nanomaterials in the construction were started since in the early 90s when during those time micro based materials was very demanding especially when dealing with High Performance Concrete (HPC). The utilization of nanobased materials improves and reinforces the cement matrix system and performs early strength and also enhances tensile properties of concrete. In this research, two types of clay were used which nanometakaolin and nanometaclay. nanometakaolin were made from sol gel process thats involved milling technique and nanometaclay were supplied by Sigma Aldrich. The mix proportion for clay based cement paste also includes metakaolin as cement replacement material. nanometakaolin and nanometaclay was added as additives from 0, 1, 3, 5, 7, 9 percent (%) from weight of cement and will be compared to OPC as control specimen. nanometakaolin and nanometaclay inclusion in cement paste will be evaluated for morphology effect by using Scanning Electron Microscope (SEM), chemical composition by using X-Ray Fluorescent (XRF) technique and strength properties. From morphology evaluation, the shape of the particles and particularisation of the matrix observed on the nanometakaolin, nanometaclay and plain cement paste were compared. Similarly, the strength of the plain cement paste shows was compared with those of nanometakaolin and nanometaclay. From the results, shows that inclusion of nanometakaolin at 7% additives generates early strength of cement paste and at 28 days of age addition of 1% of nanometakaolin was found to be the optimum addition level. The addition of 1% nanometakaolin acts as an ultra-filler and refines the microstructure of concrete. Furthermore, nanometakaolin also produces a secondary hydration product by optimizing the remaining calcium hydroxide which was not fully removed during the hydration period.

Sign in / Sign up

Export Citation Format

Share Document