Mix Proportion Of Mortar Research Articles

A Neural Network-Based Prediction of Superplasticizers Effect on the Workability and Compressive Characteristics of Portland Pozzolana Cement-Based Mortars

Portland Pozzolana Cement (PPC) mortars are predominantly employed in plastering works to achieve better workability, superior surface finish, and higher fineness to offer better cohesion with fine aggregates than the ordinary Portland cement (OPC) mortars. To achieve high performance in the cement mortar similar to cement concrete, the addition of a superplasticizer is recommended. The present study investigates the impact of addition of sulphonated naphthalene formaldehyde- (SNF)-based (0.5%, 0.6%, 0.7%, and 0.8%) and lignosulphate- (LS)-based (0.2%, 0.3%, 0.4%, and 0.5%) superplasticizers on the workability and compressive strength characteristics of PPC mortars. Plastering mortars of ratio 1 : 4 were prepared with natural sand and manufacturing sand (M sand) as fine aggregates. A flow table test was conducted on all the mortar mix proportions, and the effects of the inclusion of superplasticizers on flow properties were recorded at different time intervals (0, 30, 60, 90, and 120 minutes). PPC mortar cubes were prepared, cured, and examined to assess the inclusion of chemical admixtures on compressive strength at different ages (1, 3, 7, 14, and 28 days). The experimental findings from the workability and compressive strength of PPC mortars were analyzed, and the corresponding results were predicted using artificial intelligence. Experimental investigations demonstrated that the desired flow characteristics and higher compressive strength results were achieved from a 0.7% dosage of ligno-based superplasticizer. The predicted workability and compressive strength results at various ages acquired by implementing an Artificial Neural Network (ANN) were found to be in close agreement with the experimental results.

Self-healing of cement mortar with partial replacement of cement with silica fume

Many attempts are being made to use alternative building materials for sustainable construction practices. Huge research work being conducted to identify materials which can be partially replaced by cement. Here we tried to use silica fume & pseudomonas fluorescens as a partial replacement of cement which is having capability of self-healing in cement mortar. Efforts has been made to develop resources with minimal use of fossil fuel based on non-renewable resources which has negative impact on environment. Hence reducing ecological disturbances making biologically efficient. Many industries have been exploring way for variety of bacterial properties to introduce in construction line. Cracks occurring in cement mortar will result into the decrease in its durability property. Hence there is a great demand for effective yet eco-friendly alternative technique for reducing cracks in cement mortar. Reduction of cost can be achieved by bacterial self-healing cement mortar in terms of damage spotting and maintenance of cement mortar. This project presents effect of the bacteria (pseudomonas fluorescens) on strength and durability properties of sustainable cement mortar. Optimized bacterial concentrations of 107 cells/ml and 108 cells/ml were used for designing of mortar mix proportions. Silica fume is added at 5%, 10%, 15%, 20%, and 25% by weight of cement for replacing of cement in the 1:3 cement mortar mix. Compressive strength, split tensile strength and flexural strength tests were performed on mortar cubes at the age of 7 & 28 days. The obtained results are evident that, addition of pseudomonas fluorescens bacteria in mortar mix will enhance the mechanical and durability properties in cement mortar.

Elucidation of Microstructural and Mechanical Properties of Coconut Husk Mortar as a Sustainable Building Material for Ferrocement

The main objective of this study is to use coconut husk to produce mortar for ferrocement. Mortar mix proportions are selected per ACI codes’ recommendation and the WRD Handbook. Four types of mortars: Cement and River Sand mortar (CSM), Cement, River Sand and Steel fibre mortar (CSSFM), Cement and Coconut Husk mortar (CCHM), and Cement, River Sand (60%), Coconut Husk (40%), and Steel fibre mortar (CSCHSFM) are used for this study Microstructural studies like SEM, EDX, XRD, and FTIR analysis on cement mortar constituents and mortar mixes are studied and reported. At 3, 7, and 28 days tests of hardened mortar, such as compressive, split tensile, flexural strength, and impact strength resistance, were studied. Test results revealed that the coconut husk is innovative and sustainable and could be an alternative fine aggregate that can be utilized in place of river sand, which in turn can be used for mortar production. Since it has a lesser density which proves to be an advantage for developing lightweight mortar, it can be used for ferrocement applications.

Physicochemical characterisation of the mortars from Notre-Dame de Paris cathedral – Preliminary findings and reconstitution of the fresh mix

This work presents the results of the characterisation of the mortars used to build the vaults of the choir and a transverse arch in the nave of Notre-Dame de Paris. The aim is to highlight the mixes used and technological choices made by the builders at the end of the 12th century. A multi-analytical approach made it possible to characterise the binders, aggregates, particle size distributions and the physical and chemical properties of about thirty samples. They lead to the definition of mortar mix equivalent to medieval ones. First investigations conducted on the fresh mortar show its ability to erect an arch or the panels of the vaults and validate the mortar mix proportions. These results will sufficiently support the ongoing project on the reconstitution of compatible mortars as well as on modelling the structural comportment of the edifice.

Utilization of marble powder as fine aggregate in mortar mixes

The construction industry has been responsible for plaguing the environment due to ecological imbalance caused during the extraction and production of building materials. To make this production of construction materials cleaner, the dependency on natural resources has to be reduced. With this aim, marble powder which is a waste product generated during cutting and shaping of marble blocks has been evaluated as a replacement of conventional river sand in cement mortars. For this, four different mix proportions of mortars were evaluated in terms of workability, drying shrinkage, compressive strength, bond and adhesive strengths, density, water absorption and dynamic Young’s modulus. Results show that mortar mixes with 20% substitution of river sand by marble powder can be used for masonry and rendering purposes. Such mortars have a distinctively dense microstructure which is a consequence of reduced water requirement and formation of superior quality of hydration products. These were confirmed by scanning electron microscope, thermogravimetric analysis and Fourier transform infrared spectroscopy techniques. Hence, by replacing sand to the tune of 20% by marble powder, would enable the construction industry to reduce their dependency on river sand. Additionally, by utilizing this non-biodegradable marble waste as a building material, would reduce the burden on landfills and therefore help the marble stone industry to be more sustainable.

Development of geopolymer with pyroclastic flow deposit called Shirasu

The study presents a preliminary investigation on the applicability of Shirasu (a pyroclastic flow deposit characterized by high percentage of volcanic glass) in geopolymer. Comparative study on compressive strength and internal pore structure has been done between geopolymers with alkali activated Shirasu and fly ash as aluminosilicates. Mortar mix proportions are selected based on variations in ratio of alkaline activators to aluminosilicate and also on silica to alkali hydroxide ratio. From the experimental study, Shirasu geopolymer exhibited fairly good compressive strength. Mix proportion based on silica to alkali hydroxide ratio is observed to have profound effect on strength development.

An optimal lightweight foamed mortar mix suitable for tunnel drainage carried out using the composite lining method

In this paper, an optimal lightweight foamed mortar mix suitable is proposed for facilitating tunnel drainage carried out using the composite lining method. A physical performance evaluation and pore structure analysis is provided in order to assess the performance of different lightweight foamed mortar mix proportions with various void fractions and foam solution concentrations. Furthermore, on the basis of an in-plane permeability test that simulated the permeation of fines of soil leaking with underground water, the formation and distribution of open-cell foams by measuring the outflow characteristics and outflow volume for each mix of the nonwoven geotextile and lightweight foamed mortar, which are the existing tunnel drainage materials was examined. Consequently, a mix employing a foaming agent with a dilution rate of 2% (#1) showed a better drain performance than all the other mixes, because it had the most appropriately formed and distributed open-cell foams, the key component for tunnel drainage. In other words, the mix of dilution rate of 2% was thought to have achieved stable closed-cell foams because of the decline in the surface tension of the foams, as well as the optimal formation and distribution of open-cell foams that possess excellent permeability because of the cohesiveness between the foams. Moreover, the thickness (drainage space) of it was approximately 17 times that of the nonwoven geotextile, and because the closed-cell and open-cell foams were connected like a spider web, it could be expected to reduce the blocking of drainage caused by the fines of soil.

Waste glass sludge as a partial cement replacement in mortar

This paper presents the results of a study conducted to evaluate the possibility of utilizing the waste glass sludge (WGS) from the cutting and polishing process of glass plates, as a partial replacement of cement. A total of seven mortar mix proportions were prepared, by replacing ordinary Portland cement with WGS and/or fly ash (FA). The influences of WGS and FA on the compressive strength of mortars and ASR expansion of mortars were investigated. In addition, X-ray diffraction analysis was performed, to evaluate the pozzolanic activity. The results show that the incorporation of the WGS yields mortars with improved strengths at the later age (28days), in comparison with that of a control mortar (ordinary Portland cement only); while the WGS caused a lower early strength than that of control, but higher than that of mortars containing FA. The ASR expansion of the mortars can be reduced by incorporating WGS as effectively as by fly ash. It is found that the consumption rate of calcium hydroxide for the paste with the WGS was faster than that of paste with FA, up to 28days. These results indicate that the WGS has a higher reactivity than FA; and therefore, the WGS can be used as a pozzolanic admixture in cement composites.

Blocks for Performance of Masonry Using PET Bottle Seal: Thermal, Acoustic, and Mechanical and Evaluation

Recycling and reuse of materials is seen as the most evident solution for sustainable development. One aspect relevant to this development refers to integration of engineering to devise ways that enable the reuse of materials considered as waste, but with great potential of applicability in the building industry itself, through the generation of appropriate technologies and products that can be an alternative to social housing. So, this research aims to propose the use of PET bottles incorporated in blocks for the implementation of masonry that provides a thermal insulation in social housing. For the execution of the blocks, the PET bottles were inserted and centered in wooden molds easily made, which were subsequently filled with mortar. Three walls were executed in masonry with conventional ceramic brick, and three walls with blocks of PET for comparison of performance in thermal, acoustic, and mechanical behavior, varying the mix proportion of mortar. The thermal test consisted of preparing panels having a height of 1.20 m and a width of 1.00 m, instrumented with five thermo pair in both sides, measuring the temperatures at the surface of incidence of the heat source and on the opposite side. The acoustic performance test was done in two ways, a pure and a more complex method, using a reverberating chamber, always placing a sound source on one side and measuring the sound pressure after the wave crossed the walls already thermally tested. To obtain the mechanical performance, measurements, the same panels were tested with compression in a structures laboratory. The masonry made with PET blocks showed in thermal tests, performance similar behavior to those obtained in conventional masonry. In the acoustic tests, masonry blocks made with PET were superior to masonry with ceramic blocks. In tests concerning the mechanical performance, all three PET block walls reached greater tensile strength than those with ceramic bricks. Therefore the blocks with PET can be used as sealing bricks. Their manufacturing process is simple and could be applied for use with poor populations with the support of an institution to produce that element of construction, generating employment and income.

改質フライアッシュを混入したモルタルの収縮ひび割れ特性に関する研究

改質フライアッシュを混入したモルタルの乾燥収縮ひび割れに対する抵抗性について、混合砂と石灰砕砂を使用し、内部拘束型による一軸拘束試験を行った。その結果、混合砂はすべての供試体においてひび割れが発生したが、石灰砕砂にはひび割れが発生しなかった。また、フライアッシュがひび割れ発生に及ぼす影響については明確な結論を得ることが出来なかった。さらに、筆者らが行った既往の研究で得られたコンクリートの実験結果と比較を行った。その結果、コンクリートに比べモルタルは割裂引張強度が大きく、ひび割れ発生時の拘束応力も大きくなることが分かった。

Salt Weathering in Residential Concrete Foundations Exposed to Sulfate-bearing Ground

When a residential concrete foundation is constructed on sulfate-bearing ground, scaling of the concrete surface often arises from the crystallization and hydration pressure of the sodium sulfate that crystallizes in the pores of the concrete. Similar deterioration has been confirmed in stones and rocks and so on. This deterioration phenomenon is called “salt weathering.” We have confirmed several deterioration cases of residential concrete foundation and it is clear that such cases are widely distributed across Japan. This paper describes the results of field investigations and laboratory experiments on salt weathering of concrete. The laboratory experiment using mortar specimen shows the deterioration of mortar similar to residential concrete foundations was reproduced. We focused on the influences of the dry-wet cycle and the carbonation of the cement matrix, presuming that these are one of influential factors for salt weathering. With regard to the influence of the mix proportion of mortar, we established that low water-cement ratio has good resistance against salt weathering. However, additions to the mix proportion were not found to be effective, and the decrease in pH and the decomposition of C-S-H by carbonation are thought to affect the salt weathering resistance.

Durability of concrete exposed to leaching and external sulphate attacks

Leaching and external sulphate attack on concrete lead to dissolution of hydration products, mainly portlandite, and in case of ingress of sulphate ions to formation of expansive products such as gypsum and ettringite. Durability of concrete exposed to these environments is still based on prescriptive specifications. The aim of the study is to provide experimental data to design performance based tests and specifications for a comparative approach. Tests have been developed to study these degradations in controlled conditions at constant pH. A leaching test has been performed on concrete. Indicators can be deduced from the leaching test and they are sensitive to the variations of potential durability. An accelerated test using a high sulphate concentration has been performed on mortars. Expansion results are sensitive to mortar mix proportions and the test could be used to qualify cements or binders in a comparative approach. Concrete specimens are exposed to external sulphate attack at two levels of sulphate concentration to provide long-term data that can be used to study the relevance of the accelerated tests and models which are being developed. Results from both series of tests show a correlation between the resistance to leaching and the resistance to external sulphate attack.

A mortar mix proportion design algorithm based on artificial neural networks

The concepts of four parameters of nominal water-cement ratio, equivalent water-cement ratio, average paste thickness, fly ash-binder ratio were introduced. It was verified that the four parameters and the mix proportion of mortar can be transformed each other. The behaviors (strength, workability, et al.) of mortar primarily determined by the mix proportion of mortar now depend on the four parameters. The prediction models of strength and workability of mortar were built based on artificial neural networks (ANNs). The calculation models of average paste thickness and equivalent water-cement ratio of mortar can be obtained by the reversal deduction of the two prediction models, respectively. A mortar mix proportion design algorithm was proposed. The proposed mortar mix proportion design algorithm is expected to reduce the number of trial and error, save cost, laborers and time.

The influence of fibre-matrix interfacial bond strength on the mechanical properties of steel fibre reinforced mortars

An experimental investigation of the influence of the shear strength of the fibre-matrix interfacial bond on the mechanical properties of steel fibre reinforced cementitious mortars under uniaxial tensile and flexural loading conditions is described. The results indicate that the effect of the component of interfacial bond strength associated with the matrix mortar mix proportions on the properties of the composite is limited, but significant with respect to uniaxil tensile and first-crack flexural strengths. However, variations in the component of bond strength associated with the surface texture of the fibre primarily affect the post-crack properties of the composite, although the increased bond strength of coarsely textured (Duoform) fibres does not improve composite properties as significantly as expected on the basis of the pull-out resistance of this type of fibre. Furthermore, fibre-matrix interfacial bond strength interacts in a significant manner with two of the other factors varied in the investigation, the aspect ratio and concentration of the reinforcing fibres.