Fluid Transport Mechanisms in Portland Cement Mortar Modified with PVA and Nano Montmorillonite

2013 ◽  
Vol 687 ◽  
pp. 311-315 ◽  
Author(s):  
Teresa María Piqué ◽  
Luis Fernandez Luco ◽  
Analía Vázquez
Keyword(s):  
Tensile Strength ◽  
Portland Cement ◽  
Construction Industry ◽  
Fluid Transport ◽  
Cement Mortar ◽  
Drying Shrinkage ◽  
Cement Matrix ◽  
Poly Vinyl Alcohol ◽  
Cement Mortars ◽  
Compressive And Flexural Strengths

The development of new materials for specific applications is an increasing field in the construction industry, so is the employment of nanotechnology for this goal. When poly(vinyl alcohol) (PVA) is added to a Portland cement mortar, a film is formed in between the hydration products. This film has low elasticity modulus and high tensile strength and it enhances the mortar’s mechanical properties in the fresh and hardened states. The addition of nano montmorillonites (MMT) gives the polymer a better compatibility with the cement matrix. In this work, the changes in the microstructure of Portland cement mortars modified with PVA and PVA with MMT are assessed by means of transport of fluids capacity as an indicator. The reference is a standard mortar according to EN 196-1. The parameters measured are: weight loss under drying and air permeability. Complementary measures, such as compressive and flexural strengths and drying shrinkage have also been performed. From the obtained results, it can be concluded that the inclusion PVA + MMT to Portland cement mortar doesn’t affect the microstructure, when compared with Portland cement mortar with PVA, and even increase its tensile strength.

STUDIES ON THE ACTION OF SULPHATES ON PORTLAND CEMENT: I. THE USE OF THE EXPANSION METHOD IN THE STUDY OF THE ACTION OF SULPHATES ON PORTLAND CEMENT MORTAR AND CONCRETE

1929 ◽  
Vol 1 (3) ◽  
pp. 273-284
Author(s):  
T. Thorvaldson ◽  
D. Wolochow ◽  
V. A. Vigfusson
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Portland Cement ◽  
Cement Mortar ◽  
Expansion Method ◽  
Cement Mortars

This paper describes the methods employed in the use of expansion measurements as a means of studying the action of sulphates on Portland cement, and on Portland cement mortars. Experimental data are given dealing with the reproducibility of the expansion measurements and the relation between expansion and loss of tensile strength of mortars. Results obtained with standard sand mortars and graded sand mortars of varying richness of mix prepared from cements which differ in their resistance to sulphate action are presented.

scholarly journals AN INVESTIGATION ON THE USE OF BACILLUS SUBTILIS HU58 IN CEMENT MORTAR

2017 ◽  
Vol 7 (2) ◽  
pp. 1-8
Author(s):  
Nguyen Ngoc Tri Huynh ◽  
Nguyen Khanh Son
Keyword(s):  
Bacillus Subtilis ◽  
Calcium Carbonate ◽  
Portland Cement ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Self Healing ◽  
Curing Time ◽  
Mortar Sample ◽  
New Type ◽  
Compressive And Flexural Strengths

Literature studies reveal the fact that incorporating bacteria into cement matrix could generate the formation of precipitated product of calcium carbonate. In this work, a new type of microorganism Bacillus subtilis HU58 was used as mixing component in formulating mortar sample of Portland cement and the effectiveness of self-healing character after 1 year of curing time was observed. Results showed the consequence in the enhancement of both compressive and flexural strengths of bacteria-modified mortar while comparing to a controlled mortar: 60MPa>56MPa (in compression) and 11MPa >9MPa (in flexion). Furthermore, those pre-existing artificial cracks 1mm in width of the prismatic mortar 40x40x160mm filled up partially (self-healing) by mineral glue.

scholarly journals Mechanical Properties and Microstructure of Polyvinyl Alcohol (PVA) Modified Cement Mortar

2019 ◽  
Vol 9 (11) ◽  
pp. 2178 ◽  
Author(s):  
Jie Fan ◽  
Gengying Li ◽  
Sijie Deng ◽  
Zhongkun Wang
Keyword(s):  
Mechanical Properties ◽  
Polyvinyl Alcohol ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Hydration Products ◽  
Scanning Calorimetry ◽  
Large Piece ◽  
Cement Mortars ◽  
Compressive And Flexural Strengths ◽  
Scanning Electron

The mechanical properties of cement mortars with 0~2.0% (by mass) polyvinyl alcohol (PVA) were experimentally studied, and the effects of PVA incorporation on the hydration products and microstructure of the cement mortar were determined with differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results show that the rational content of PVA formed evenly dispersed network-like thin films within the cement matrix, and these network-like films can bridge cracks in the cement matrix and improve the mechanical properties of the cement mortar. Over- incorporation of PVA may result in the formation of large piece polymer films that coat the cement particles, delay the hydration of the cement mortar and adversely affect its performance. The mechanical properties of the cement mortar show a significant increase and then decrease with a change in the PVA incorporation. When the PVA content was 0.6% and 1.0%, the mortar had the best compressive and flexural strengths, respectively. The compressive strength of the cement mortar increased by 12.15% for a PVA content of 0.6%, and the flexural strength of the cement mortar increased by 24.83% for a PVA content of 1.0%.

scholarly journals Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mao-chieh Chi ◽  
Jiang-jhy Chang ◽  
Ran Huang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Liquid Slag ◽  
Drying Shrinkage ◽  
Curing Temperature ◽  
Alkali Activated Slag ◽  
Cement Mortars ◽  
Activated Slag ◽  
Alkali Activated

The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.

STUDIES ON THE ACTION OF SULPHATES ON PORTLAND CEMENT: II. STEAM-CURING OF PORTLAND CEMENT MORTAR AND CONCRETE AS A REMEDY FOR SULPHATE (ALKALI) ACTION

1929 ◽  
Vol 1 (4) ◽  
pp. 359-384 ◽  
Author(s):  
T. Thorvaldson ◽  
V. A. Vigfusson ◽  
D. Wolochow
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Laboratory Study ◽  
Cement Mortar ◽  
Steam Curing ◽  
Cement Mortars ◽  
Sodium Magnesium ◽  
The Stability

A study was made of the effect of steam-curing at various temperatures between 50° and 200 °C. on the resistance of Portland cement mortars to the action of solutions of the sulphates of sodium, magnesium and calcium. The methods used consisted in comparing the expansion of steam-cured and untreated mortar specimens during exposure to the solutions, and in determining the changes in the tensile strength of the more resistant mortars after long periods of exposure.A laboratory study of steam-curing as a remedy for the action of sulphates ("alkali") on Portland cement mortars, was made by determining the effect on the stability of the mortar as indicated by changes in volume and in tensile strength on exposure to sulphate solutions at 21 °C. The effect of steam-curing on the tensile and compressive strength of mortars and concrete was also studied.

scholarly journals Application of novel synthesized nanocomposites containing κ-carrageenan/PVA/eggshell in cement mortars

2020 ◽  
Vol 70 (340) ◽  
pp. 235
Author(s):  
I. Sanrı-Karapınar ◽  
A. O. Pehlivan ◽  
S. Karakuş ◽  
A. E. Özsoy-Özbay ◽  
A. U. Yazgan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Cementitious Composites ◽  
Triple Combination ◽  
Strain Capacity ◽  
Preliminary Attempt ◽  
Cement Mortars ◽  
Compressive And Flexural Strengths ◽  
First Time

This study is a preliminary attempt to present the preparation and the first time a κ-carrageenan/PVA/eggshell nanostructure is used as a novel biodegradable and homogeneous nanostructure in cement composition. In order to clearly understand the effects these additives have on the mechanical properties of cementitious composites, they were synthesized in double and triple combinations and added into mortar mixtures. Three different cement mortar specimens were prepared by integrating the additives in ratios of 0, 0.1, 0.5 and 1% by cement weight and flexural and compressive strengths of the specimens were determined at the ages of 7 and 28 days. The flowability of the presented nanostructures was also discussed. The results revealed a 10–11% increase in both compressive and flexural strengths for the specimens prepared with the triple combination of the proposed additives. Moreover, strain capacity was enhanced as a result of the efficient dispersion of additives in the cement matrix.

scholarly journals Preparation and Mechanical Properties of Graphene Oxide: Cement Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fakhim Babak ◽  
Hassani Abolfazl ◽  
Rashidi Alimorad ◽  
Ghodousi Parviz
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Cement Composites ◽  
Xrd Diffraction ◽  
Calcium Silicate Hydrates ◽  
The Matrix ◽  
Scanning Electron

We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.

scholarly journals Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber

2017 ◽  
Vol 67 (326) ◽  
pp. 119 ◽  
Author(s):  
Zhengqi Li
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortar ◽  
Drying Shrinkage ◽  
High Strength ◽  
Fiber Content ◽  
Fine Aggregate ◽  
Aggregate Content ◽  
Normal Strength ◽  
Gardner Model

The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete.

STUDIES ON THE ACTION OF SULPHATES ON PORTLAND CEMENT: III. THE EFFECT OF THE ADDITION OF SILICA GEL TO PORTLAND CEMENT MORTARS ON THEIR RESISTANCE TO SULPHATE ACTION

1929 ◽  
Vol 1 (5) ◽  
pp. 385-399
Author(s):  
T. Thorvaldson ◽  
V. A. Vigfusson ◽  
D. Wolochow
Keyword(s):  
Tensile Strength ◽  
Portland Cement ◽  
Silica Gel ◽  
Magnesium Sulphate ◽  
Calcium Sulphate ◽  
Cement Mortars

The effect of substituting silica gel for a portion of the Portland cement in standard and graded-sand mortars on the expansion and loss in strength of the mortars in sulphate solutions was determined. Portland cement silica gel sand mortars were cured in steam at 100 °C. and the effect on their sulphate resistance measured; the behavior of lime-silica gel sand mortar in solutions of sodium and magnesium sulphate was also studied. It was found that the addition of silica gel to the mortar, very effective in preventing expansion and maintaining the tensile strength of the mortar in solutions of sodium, and calcium sulphate, was not so effective in solutions of magnesium sulphate. Steam-cured mortars containing silica gel to the extent of 20% of the cement present showed a slightly greater resistance to the action of solutions of sodium and calcium sulphates, but less resistance in solutions of magnesium sulphate, than similar steam-cured mortars containing no silica gel. Lime-silica gel sand mortars behaved very similarly in sulphate solutions as Portland cement mortars containing silica gel. The possible causes of the effects produced by the addition of silica gel to Portland cement mortars are considered, and several explanations discussed.

Study on the reinforcing mechanisms of nano silica to cement-based materials with theoretical calculation and experimental evidence

2016 ◽  
Vol 50 (29) ◽  
pp. 4135-4146 ◽  
Author(s):  
Liqing Zhang ◽  
Ning Ma ◽  
Yunyang Wang ◽  
Baoguo Han ◽  
Xia Cui ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Theoretical Calculation ◽  
Interfacial Transition Zone ◽  
Cement Matrix ◽  
Nano Silica ◽  
X Ray ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Compressive And Flexural Strengths ◽  
Curing Age

Cement mortars with different contents of nano silica (NS) were fabricated and tested. Their compressive and flexural strengths showed significant increases. Theoretical calculation and thermogravimetry (TG) analysis, scanning electron microscope (SEM) and X-Ray powder diffraction (XRD), and electrical resistivity test were used to analyze the reinforcing mechanisms of NS. Theoretically, consumed calcium hydroxide (CH) increases with NS content, which indicates that NS has huge potential to react with CH. According to the results of TG, the amount of consumed CH increases and agrees with theoretical calculation when the content of NS is less than 1.5%. However, a plateau is achieved for the mass of consumed CH in results of TG when the content of NS exceeds 1.5%. SEM shows that NS can make matrix dense and also reduce the size of CH in matrix beside interfacial transition zone (ITZ). The results of XRD prove that NS can change the tendency of crystal of CH in cement matrix. However, the change degree of tendency of crystal of CH in cement matrix is lower than that in ITZ. The change trends of electrical resistivity with increasing NS content and curing age are similar with those of flexural and compressive strengths. This indicates that electrical resistivity can reflect strength and structural compactness of cement matrix.

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