Assessing Rheological Properties of Cement Paste as a First Step in Predicting Robustness of Self-compacting Concrete

2018 ◽  
Vol 69 (7) ◽  
pp. 1733-1739
Author(s):  
Marius Dumitrescu ◽  
Alina Badanoiu ◽  
Constantin Dorinel Voinitchi ◽  
Georgeta Voicu
Keyword(s):  
Cement Paste ◽  
Rheological Behavior ◽  
Cement Hydration ◽  
Great Influence ◽  
Hydration Process ◽  
X Ray Diffraction ◽  
Self Compacting Concrete ◽  
Binder Ratio ◽  
Early Strength ◽  
Water To Binder Ratio

This paper proposes a methodology to assess the rheological behavior of cement paste as a first step to linking this behavior to the robustness of the Self Compacting Mortar (SCM) and further extending this to Self-Compacting Concrete (SCC). Cement paste�s rheological behavior was assessed in terms of spread (using a mini-cone) and time of flow (using the Marsh cone). The results show that the type of superplasticizer (SP) admixture has a great influence on the rheological behavior of cement paste and for each combination of binder and superplasticizer admixture there is a specific range of water to binder ratio in which the rheology of paste seems to be appropriate for obtaining a robust SCC mix. The influence of SP and limestone filler addition on the kinetic of cement hydration process was assessed by X Ray Diffraction and thermal analysis (TG-DTA). Based on these results, i.e. an important delaying effect exerted by superplasticizer additions on cement hydration process at early ages (1 day), it can be concluded that when designing SCC for the precast industry - where the early strength of concrete is of high importance, analyzing the early strength of binder paste together with the robustness properties is very important. The correlation between the two aspects - rheology and early strength -is very important in this case in order to obtain applicable results in practice.

Effect of Zeolite on Early Strength of Portland Cement Mortars

2019 ◽  
Vol 798 ◽  
pp. 358-363
Author(s):  
Raphat Tanasalagul ◽  
Thammaros Pantongsuk ◽  
Thapanee Srichumpong ◽  
Jaroon Junsomboon ◽  
Wichit Prakaypan ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortar ◽  
Testing Machine ◽  
Type I ◽  
X Ray Diffraction ◽  
Cement Mortars ◽  
Binder Ratio ◽  
Early Strength ◽  
Water To Binder Ratio

Portland cement consists essentially of compounds of lime mixed with silica and alumina whereas zeolite is a kind of minerals containing high content of reactive silica and alumina. Therefore, there is a probability to apply zeolite in cement mortar in order to develop mortar properties. The purpose of this research was to study and analyze the efficiency of zeolite addition on properties of cement mortar. X-ray diffraction (XRD), universal testing machine (UTM) and scanning electron microscope (SEM) were used to characterize for mortar specimens. Mechanical property test was compressive strength according to ASTM C109 and carried out on 5 x 5 x 5 cm3 cube specimens at 1, 7 and 28 curing days. In this research, cement mortars were prepared by mixing type I Portland cement, fly ash, sand and zeolite. Zeolite was varied as 0, 0.25, 0.50 and 0.75 wt.% to cement and w/b (water to binder ratio) was 0.48. The results presented that the compressive strength of mortar with small amount of zeolite was improved since 1day age obviously comparing to that of mortar without zeolite. It was confirmed that zeolite would help strengthening the cement mortars at early strength.

Effect of Fly Ash and Nano-CaCO3 on the Viscosity of Cement Paste

2013 ◽  
Vol 357-360 ◽  
pp. 968-971 ◽  
Author(s):  
Ren Juan Sun ◽  
Zhi Qin Zhao ◽  
Da Wei Huang ◽  
Gong Feng Xin ◽  
Shan Shan Wei ◽  
...  
Keyword(s):  
Fly Ash ◽  
Cement Paste ◽  
Bingham Model ◽  
Reduced Viscosity ◽  
Binder Ratio ◽  
Water To Binder Ratio

The effect of fly ash and nanoCaCO3 on the viscosity of pastes was studied. The rheological value of cement paste was determined by the rotation rheometer NXS-11B. In the study, five different dosages (0%, 20%, 30%, 40%, and 50%) of fly ash and three levels of nanoCaCO3, 0.5%, 1%, and 2.5%, were considered. Viscosity of the pastes, made with fly ash and nanoCaCO3 at a constant water-to-binder ratio of 0.35, were measured and analyzed. The results indicate that the pastes with fly ash or/and nanoCaCO3 still fit the Bingham model. The addition of fly ash reduced viscosity, however, the addition of nanoCaCO3 increased viscosity. The effect of nanoCaCO3 is more significantly than fly ash on viscosity.

scholarly journals Effect of nano-SnO2 on early-age hydration of Portland cement paste

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985194 ◽  
Author(s):  
Jianping Zhu ◽  
Genshen Li ◽  
Ruijie Xia ◽  
Huanhuan Hou ◽  
Haibin Yin ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Cement Hydration ◽  
Cementitious Materials ◽  
Hydration Process ◽  
Strength Development ◽  
Early Age ◽  
Test Machine ◽  
Portland Cement Paste ◽  
Scanning Electron

Nanomaterial, as a new emerging material in the field of civil engineering, has been widely utilized to enhance the mechanical properties of cementitious material. Nano-SnO2 has presented high hardness characteristics, but there is little study of the application of nano-SnO2 in the cementitious materials. This study mainly investigated the hydration characteristics and strength development of Portland cement paste incorporating nano-SnO2 powders with 0%, 0.08%, and 0.20% dosage. It was found that the early-age compressive strength of cement paste could be greatly improved when nano-SnO2 was incorporated with 0.08% dosage. The hydration process and microstructure were then measured by hydraulic test machine, calorimeter, nanoindentation, X-ray diffraction, scanning electron microscope, and mercury intrusion porosimetry. It was found that the cement hydration process was promoted by the addition of nano-SnO2, and the total amount of heat released from cement hydration is also increased. In addition, the addition of nano-SnO2 can promote the generations of high density C-S-H and reduce the generations of low density C-S-H indicating the nucleation effect of nano-SnO2 in the crystal growth process. The porosity and probable pore diameter of cement paste with 0.08% nano-SnO2 were decreased, and the scanning electron microscopic results also show that the cement paste with 0.08% nano-SnO2 promotes the densification of cement microstructure, which are consistent with the strength performance.

scholarly journals EARLY AGE POROSITY AND PORE SIZE DISTRIBUTION OF CEMENT PASTE WITH FLUE GAS DESULPHURISATION (FGD) WASTE

2013 ◽  
Vol 19 (5) ◽  
pp. 622-627 ◽  
Author(s):  
Jamal M. Khatib ◽  
Pritpal S. Mangat ◽  
Lee Wright
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Cement Paste ◽  
Flue Gas ◽  
Early Stage ◽  
Early Age ◽  
Cement Pastes ◽  
Binder Ratio ◽  
Water To Binder Ratio

This paper is part of a wide-ranging investigation on the use of flue gas desulphurisation (FGD) waste in cement-based materials. It reports the results on the porosity and pore size distribution of cement paste containing varying amounts of simulated FGD waste. The water to binder ratio was 0.5. The binder consists of cement and simulated FGD. The FGD is a combination of fly ash and gypsum ranging from 0% to 100%. Cement in the pastes was partially replaced with 25% FGD (by weight). The porosity and pore size distribution of cement pastes was determined during the early stage of hydration. Increasing the amount of gypsum does not increase the pore volume. However, increasing the amount of gypsum in the paste leads to an increase in the threshold diameter and a decrease in the percentage of small pores in the paste, both indicating a coarser pore structure. The results of this investigation were compared with data at longer curing periods.

Investigation and Prediction for Carbonation Resistance of Ready-Mixed Concrete in Qinhuangdao City

2011 ◽  
Vol 71-78 ◽  
pp. 4981-4984
Author(s):  
Xiao Hui Li ◽  
Jin Rui Zhang ◽  
Ran Ran Zhao ◽  
Wei Zheng
Keyword(s):  
Mass Fraction ◽  
Great Influence ◽  
Mineral Admixture ◽  
Carbonation Depth ◽  
Service Period ◽  
Carbonation Resistance ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Ready Mixed Concrete ◽  
Mixed Concrete

The carbonation resistance of ready-mixed concrete in Qinhuangdao was investigated and the predicted experimental data indicated that the carbonation resistance of concrete in Qinhuangdao was unsatisfactory. The longest predicted service period of concretes in this survey is merely 39.1 years when the carbonation depth reaches 25 mm; and the shortest is only 8.7 years. It’s awfully difficult to guarantee the durability of reinforced concrete structures for 50 years. The experiment results also shows that both the water to binder ratio and the mineral admixture mass fraction have great influence on the carbonation resistance of concrete. With the decrease of water to binder ratio and mineral admixture mass fraction, the predicted service years of ready-mixed concrete increase dramatically.

scholarly journals High-Performance Grouting Mortar Based on Mineral Admixtures

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Cong Ma ◽  
Yuehu Tan ◽  
Erbing Li ◽  
Yinsuo Dai ◽  
Meng Yang
Keyword(s):  
High Performance ◽  
Setting Time ◽  
High Strength ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Binder Ratio ◽  
The Common ◽  
Water To Binder Ratio

A study on high-performance grouting mortar is reported. The common mortar was modified by mineral admixtures such as gypsum, bauxite, and alunite. The effects of mineral admixtures on the fluidity, setting time, expansion, strength, and other properties of mortar were evaluated experimentally. The microstructure of the modified mortar was characterized by X-ray diffraction, scanning electron microscopy, and mercury intrusion porosimetry. Moreover, the expansive performance and strength of the grouting mortar were verified by anchor pullout test. The results show that the best conditions for gypsum-bauxite grouting mortar are as follows: a water-to-binder ratio of 0.3, a mineral admixture content of ~15%, and a molar ratioKof 2. The ultimate bearing capacity of the gypsum-bauxite grouting mortar anchor increased by 39.6% compared to the common mortar anchor. The gypsum-bauxite grouting mortar has good fluidity, quick-setting, microexpansion, early strength, and high strength performances.

scholarly journals Study on adsorption, rheology and hydration behaviours of Polycarboxylate(PCE) superplasticizer synthesized by different acid to ether ratio

2021 ◽  
Vol 2133 (1) ◽  
pp. 012007
Author(s):  
Zhijun Lin ◽  
Xiaofang Zhang ◽  
Zhanhua Chen ◽  
Yue Xiao ◽  
Yunhui Fang
Keyword(s):  
Molecular Weight ◽  
Adsorption Capacity ◽  
Cement Paste ◽  
Cement Hydration ◽  
Main Chain ◽  
Chain Structure ◽  
Hydration Process ◽  
Side Chain ◽  
Structure Parameters ◽  
Polycarboxylate Superplasticizer

Abstract Polycarboxylate superplasticizer is synthesised by different acid to ether ratio, which is changing the main chain structure parameters, obtained different microstructures. The effect of different microstructure PCE superplasticizer on the fluidity of cement paste, rheological thixotropy, adsorption capacity and hydration heat are studied. The results show that dispersing performance in cement with acid to ether ratio of 3.5 is the best, the molecular weight and side chain density have rather little effect on the cement hydration process.

scholarly journals INFLUENCE OF SILICA COLLOID ON RHEOLOGY OF CEMENT PASTE WITH SUPERPLASTICIZER

2017 ◽  
Vol 25 (1) ◽  
pp. 73-80
Author(s):  
T.H. Chuong ◽  
P.V. Nga
Keyword(s):  
Experimental Data ◽  
Rheological Property ◽  
Silica Fume ◽  
Cement Paste ◽  
Rheological Behavior ◽  
Concrete Mixture ◽  
Silica Colloid ◽  
Binder Ratio ◽  
High Silica ◽  
Water Binder Ratio

Information of rheological behavior of binder paste is important for proportioning high slump concrete mixture at low water to cement ratios. This paper presents experimental data on the rheological property of silica colloid incorporated binder paste using naphthalene based and polycarboxylate based superplasticizer, compared to that of silica fume incorporated binder paste. Experimental data showed that silica colloid incorporated binder is compatible to tested superplasticizers in the all investigated range of silica colloid content, whereas the pastes incorporated with high silica fume content (over 10%) indicated incompatibility, especially to naphthalene based superplasticizer. There was also found out saturated content of superplasticizer corresponding to every kind of binder and water-binder ratio, with and without set retarding admixture. 

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