scholarly journals Analysis Technique on Water Permeability in Concrete with Cold Joint considering Micro Pore Structure and Mineral Admixture

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Se-Jin Choi ◽  
Suk-Pyo Kang ◽  
Sang-Chel Kim ◽  
Seung-Jun Kwon
Keyword(s):  
Water Permeability ◽  
Mineral Admixture ◽  
Portland Cement Concrete ◽  
Replacement Ratio ◽  
Water Permeation ◽  
Analysis Technique ◽  
Binder Ratio ◽  
Joint Width ◽  
Water To Binder Ratio ◽  
Representative Element Volume

Cold joint in concrete due to delayed concrete placing may cause a reduced shear resistance and increased water permeation. This study presents an analytical model based on the concept of REV (Representative Element Volume) to assess the effect of water permeability in cold joint concrete. Here, OPC (Ordinary Portland Cement) concrete samples with cold joint are prepared and WPT (Water Permeability Test) is performed on the samples cured for 91 days. In order to account for the effect of GGBFS (Granulated Ground Blast Furnace Slag) on water permeability, concrete samples with the same W/B (Water to Binder) ratio and 40% replacement ratio of GGBFS are tested as well. Utilizing the previous models handling porosity and saturation, the analysis technique for equivalent water permeability with effective cold joint width is proposed. Water permeability in cold joint increases to 140.7% in control case but it decreases to 120.7% through GGBFS replacement. Simulation results agree reasonably well with experimental data gathered for sound and cold joint concrete.

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.

Analysis of the Effect of Fly Ash on Compressive Strength of Concrete Using Neural Network and Parameter Analysis

2020 ◽  
Vol 995 ◽  
pp. 130-135
Author(s):  
Xiao Yong Wang
Keyword(s):  
Neural Network ◽  
Compressive Strength ◽  
Fly Ash ◽  
Network Model ◽  
Neural Network Model ◽  
Parameter Analysis ◽  
Replacement Ratio ◽  
The Neural Network ◽  
Binder Ratio ◽  
Water To Binder Ratio

Compressive strength is a crucial design index of fly ash blended concrete. This study presents an estimation model to show the effect of fly ash on the strength development of concrete. First, a neural network model is proposed to estimate the compressive strength of fly ash blended concrete. The input variables of the neural network are water-to-binder ratio, fly ash replacement ratio, and curing ages. The output result of the neural network is a strength. The range of water-to-binder ratio is from 0.3 to 0.5, the range of fly ash replacement ratio is from 0 to 0.55, and the range of test age is from 3 days to 180 days. The neural network gives an accurate evaluation of compressive strength. Second, parameter analysis is carried out based on the neural network model. The results of parameter analysis show that the effect of fly ash on strength is dependent on water-to-binder ratio. The using of high-volume fly ash with low water-to-binder ratio concrete is a rational option.

Experimental Study on Salt Solution Ingress into Concrete under Capillary Siphon Effect

2010 ◽  
Vol 150-151 ◽  
pp. 788-791
Author(s):  
Kun Lin Ma ◽  
You Jun Xie ◽  
Guang Cheng Long ◽  
Jian Huang
Keyword(s):  
Pore Structure ◽  
Salt Solution ◽  
Influence Factors ◽  
Mineral Admixture ◽  
Test Results ◽  
Binder Ratio ◽  
Water Test ◽  
Concrete Materials ◽  
Short Time ◽  
Water To Binder Ratio

Salt solution ingress into concrete will result in serious deterioration of concrete materials, and then bring concrete structure in danger. So researchers pay more attention to the transportation of salt solution in concrete. In this paper, the ingress of 5% NaCl, 5%Na2SO4 and H2O into concrete under capillary siphon effect were investigated, and the influence factors such as water to binder ratio, mineral admixture, porosity and pore structure were also analyzed by methods of capillary solution-absorption experiment and evaporated water test. Results show that in capillary siphon effect, first the salt solution ingress into concrete increase quickly in very short time and then with the increase of time the solution absorption mass keep stable gradually. The types of salt solution are not the decisive factors controlling the solution ingress. Addition proper mineral admixture such as compound of fly ash (FA) and silica fume (SF) can decrease solution absorption mass under capillary siphon effect efficiently. In capillary effect, pores with aperture above 30 nm have close relativity with solution absorption mass. The decrease of porosity and improvement of pore structure can reduce the ingress of solution into concrete.

scholarly journals Reuse of Sintered Sludge from Municipal Sewage Treatment Plants for the Production of Lightweight Aggregate Building Mortar

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 999
Author(s):  
Changyong Li ◽  
Xiaoyan Zhang ◽  
Bingxin Zhang ◽  
Yunfei Tan ◽  
Fenglan Li
Keyword(s):  
Fly Ash ◽  
Sewage Treatment ◽  
Lightweight Aggregate ◽  
Limestone Powder ◽  
Municipal Sewage ◽  
Dry Density ◽  
Replacement Ratio ◽  
Sewage Treatment Plants ◽  
Binder Ratio ◽  
Water To Binder Ratio

In recent years, the sludge produced by municipal sewage treatment plants has become an important recyclable resource for producing green building materials. After the systematic processing of incineration and particle formation, the sintered sludge can be processed into fine lightweight aggregate to produce building mortar with the controlled leaching of heavy metals and radioactivity. In this paper, to increase its economic and environmental benefits, mortar with sintered sludge aggregate was made by cement admixing of fly ash or limestone powder. The water-to-binder ratio was set at three levels—0.82, 0.68, and 0.62—and either flay ash or limestone powder was used to replace equal masses of cement at 10%, 20%, or 30%. Eighteen groups of mortar were studied to evaluate their workability, air content, compressive strength, tensile adhesive strength, dry density, and thermal conductivity. The results indicate that with a proper water-to-binder ratio, and the replacement ratio of fly ash or limestone powder, the mortar can be produced with good workability, consistency, water-retention rate, layering degree, and setting time. The mortar made with sintered sludge lightweight aggregate, designated by the mix-proportion method for conventional lightweight aggregate mortar, did not meet the target strength, although the compressive strength of mortar was no less than 3.0 MPa, which meets the strength grade M2.5. The tensile adhesive strength reached 0.18 MPa. The mortar was super lightweight with a dry density less than 400 kg/m3, and a thermal conductivity within 0.30~0.32 W/(m⋅K). The effects of water-to-binder ratio and replacement ratio of fly ash or limestone powder on the above properties are discussed with test results. The study provides a basis for using sintered sludge lightweight aggregate for building mortar.

Support Vector Machine (SVM)-Based Optimal Design Procedure of Fly Ash Blended Concrete

2021 ◽  
Vol 894 ◽  
pp. 103-108
Author(s):  
Tae Wan Kim ◽  
Jong Yeon Lim ◽  
Xiao Yong Wang ◽  
Yi Han
Keyword(s):  
Support Vector Machine ◽  
Compressive Strength ◽  
Fly Ash ◽  
Optimal Design ◽  
Design Procedure ◽  
Support Vector ◽  
Replacement Ratio ◽  
Svm Model ◽  
Binder Ratio ◽  
Water To Binder Ratio

A support vector machine (SVM) is widely used for predicting the properties of fly ash blended concrete. However, the studies about the optimal design of fly ash blended concrete based on SVM are very limit. This study shows an SVM-based optimal design procedure of fly ash blended concrete. First, we built an SVM model and evaluated the compressive strength of fly ash blended concrete considering the effects of water to binder ratio, fly ash replacement ratio, and test ages. Second, we made parameter studies based on the SVM model. The parameter studies show that fly ash can improve the late age strength of concrete. This improvement is obvious for concrete with lower water to binder ratio. The optimal fly ash replacement ratio increases as the water to binder ratio decreases.

scholarly journals Enhanced Metakaolin Reactivity in Blended Cement with Additional Calcium Hydroxide

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 367
Author(s):  
Kira Weise ◽  
Neven Ukrainczyk ◽  
Aaron Duncan ◽  
Eduardus Koenders
Keyword(s):  
Calcium Hydroxide ◽  
Blended Cement ◽  
Initial Mixture ◽  
Pozzolanic Reaction ◽  
Replacement Ratio ◽  
Pozzolanic Reactivity ◽  
Thermogravimetric Data ◽  
Binder Ratio ◽  
Water To Binder Ratio ◽  
Mass Balance Approach

This study aims to increase the pozzolanic reactivity of metakaolin (MK) in Portland cement (PC) blends by adding additional calcium hydroxide (CH_add) to the initial mixture. Cement paste samples were prepared with PC, MK and water with a water-to-binder ratio of 0.6. Cement replacement ratios were chosen from 5 to 40 wt.% MK. For higher replacement ratios, i.e., 20, 30 and 40 wt.% MK, CH_add was included in the mixture. CH_add-to-MK ratios of 0.1, 0.25 and 0.5 were investigated. Thermogravimetric analysis (TGA) was carried out to study the pozzolanic reactivity after 1, 7, 28 and 56 days of hydration. A modified mass balance approach was used to normalize thermogravimetric data and to calculate the calcium hydroxide (CH) consumption of samples with CH_add. Results showed that, without CH_add, a replacement ratio of 30 wt.% or higher results in the complete consumption of CH after 28 days at the latest. In these samples, the pozzolanic reaction of MK turned out to be restricted by the amount of CH available from the cement hydration. The increased amount of CH in the samples with CH_add resulted in an enhanced pozzolanic reaction of MK as confirmed by CH consumption measurements from TGA.

scholarly journals Salt-Frost Scaling of Concrete with Slag and Fly Ash - Influence of Carbonation and Prolonged Conditioning on Test Results

2020 ◽  
Vol 63 (2) ◽  
pp. 89-108
Author(s):  
Elisabeth Helsing ◽  
Peter Utgenannt
Keyword(s):  
Fly Ash ◽  
Frost Resistance ◽  
Test Results ◽  
Portland Cement Concrete ◽  
Supplementary Cementitious Material ◽  
Granulated Blast Furnace Slag ◽  
Binder Ratio ◽  
Swedish Experience ◽  
Entrained Air ◽  
Water To Binder Ratio

AbstractAccording to Swedish experience the slab method in CEN/TS 12390-9 is successful in predicting the salt-frost resistance of Portland cement concrete. However, doubts have been raised whether the same can be said when used on concrete with supplementary cementitious material, e.g. fly ash or ground granulated blast furnace slag (GGBS). Test results from concrete mixes with up to 35 % fly ash 65 % GGBS, with two different Portland cements and a water-to-binder ratio of 0.45 are presented in this paper. The tests were carried out with the standard method and with five modifications concerning the pre-conditioning of the specimens before freeze-thaw cycling. The age of the specimens at sawing was increased, the time in 65 % RH was prolonged and exposure to 1 % CO2-environment was used. The results show that for air-entrained concrete with fly ash or GGBS both prolonging the exposure to 65 % RH and exposure to CO2 diminishes the salt-frost resistance. The influence increases with increasing amount of fly ash or GGBS. However, the type of cement also has a certain influence. The influence of exposure to CO2 on the salt-frost resistance of concrete without entrained air was totally different from the influence on concrete with entrained air.

Water permeability of apical and basolateral cell membranes of rat inner medullary collecting duct

1990 ◽  
Vol 259 (6) ◽  
pp. F986-F999 ◽  
Author(s):  
B. Flamion ◽  
K. R. Spring
Keyword(s):  
Water Flow ◽  
Water Permeability ◽  
Cell Membranes ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Volume Regulatory Decrease ◽  
Water Permeation ◽  
Inner Medullary Collecting Duct ◽  
Medullary Collecting Duct

To quantify the pathways for water permeation through the kidney medulla, knowledge of the water permeability (Posmol) of individual cell membranes in inner medullary collecting duct (IMCD) is required. Therefore IMCD segments from the inner two thirds of inner medulla of Sprague-Dawley rats were perfused in vitro using a setup devised for rapid bath and luminal fluid exchanges (half time, t1/2, of 55 and 41 ms). Differential interference contrast microscopy, coupled to video recording, was used to measure volume and approximate surface areas of single cells. Volume and volume-to-surface area ratio of IMCD cells were strongly correlated with their position along the inner medullary axis. Transmembrane water flow (Jv) was measured in response to a variety of osmotic gradients (delta II) presented on either basolateral or luminal side of the cells. The linear relation between Jv and delta II yielded the cell membrane Posmol, which was then corrected for membrane infoldings. Basolateral membrane Posmol was 126 +/- 3 microns/s. Apical membrane Posmol rose from a basal value of 26 +/- 3 microns/s to 99 +/- 5 microns/s in presence of antidiuretic hormone (ADH). Because of amplification of basolateral membrane, the ADH-stimulated apical membrane remained rate-limiting for transcellular osmotic water flow, and the IMCD cell did not swell significantly. Calculated transcellular Posmol, expressed in terms of smooth luminal surface, was 64 microns/s without ADH and 207 microns/s with ADH. IMCD cells in anisosmotic media displayed almost complete volume regulatory decrease but only partial volume regulatory increase.

Effects of Two Polypropylene Fibers on the Properties of High Strength Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1328-1331
Author(s):  
Bai Rui Zhou ◽  
Dong Dong Han ◽  
Jian Hua Yang ◽  
Yi Liang Peng ◽  
Guo Xin Li
Keyword(s):  
Portland Cement ◽  
Modulus Of Elasticity ◽  
High Strength Concrete ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Polypropylene Fibers ◽  
Strength Concrete ◽  
Reticular Fiber ◽  
Binder Ratio ◽  
Water To Binder Ratio

Portland cement, crushed stone, sand and superplasticizer were used to obtain a high strength concrete with a low water to binder ratio. A reticular polypropylene fiber and a single polypropylene fiber were used to improve the strength of the high strength concrete, but the effects of the two fibers on the slump and strengths were quite different. The reasons of the differences were the surface area and the modulus of elasticity of the fibers. The results show the reticular fiber was better to used in high strength concretes.

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