Normal Mortar Research Articles

Chloride ingress and binding of coral waste filler-coral waste sand marine mortar incorporating metakaolin

The present study investigates the chloride ingress and binding behaviors of coral waste filler-coral waste sand marine mortar and the influence imposed by metakaolin (MK) addition. The mortars were cured for 4 months and followed by exposing to 0.5 M sodium chloride solution for 45 days. Thereafter, the chloride profiles of mortars were determined by titration method and the phase assemblies of mortars at different depths were determined by X-ray diffraction and thermogravimetry. The results show that coral waste mortars demonstrate dramatically lower ability to resist chloride ingress than normal mortar due to the loose structure of coral waste mortar. Due to the combination of pozzolanic reaction, formation of additional carboaluminate and improved chloride binding capacity by MK addition, chloride penetration is significantly restrained. Carboaluminate can decompose to possible solid solution between hemicarboaluminate (C4Ac0.5H12) and Friedel’s salt (C4ACl2H10) in a low chloride concentration, while it directly converts to Friedel’s salt in a high chloride concentration. Since the large amount of coral waste in system restrains the formation of monosulfoaluminate (C4AsH12), the Kuzel’s salt (C4As0.5ClH12), as an intermediate phase from monosulfoaluminate to Friedel’s salt, is not formed even in low chloride concentration. Owing to the synergistic effects of carbonation and the leaching of calcium ions, the outmost layers of the mortars bind less chloride compared to their neighboring layers.

Effect of Using Cement Kiln Dust as a Nano-Material on the Strength of Cement Mortars

In this experimental study, the effects of using nano-sized Cement Kiln Dust (CKD) as a partial replacement for Ordinary Portland Cement (OPC) on the strength of cement mortars is investigated. The CKD was milled up to 4 hours in a planetary ball mill. In addition to the control cement mortar mixture with 0% CKD, a total of 28 concrete mortar mixtures were prepared with four different replacement percentages of nano-CKD (5, 10, 15, and 20 %), and seven different milling times (1, 1.5, 2, 2.5, 3, 3.5, and 4 hours). The compressive strengths of all cement mortar mixtures were evaluated after curing periods of 7, 28, and 56 days. In addition, the chemical, physical and microscopical properties of the nano-CKD were evaluated using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and X-ray diffraction (XRD). The experimental results showed that the partial replacement of the OPC with the nano-CKD enhanced the compressive strength of the cement mortar by about 15-30% compared with normal mortar without CKD. Moreover, the experimental results indicated that no change was observed in the chemical composition of CKD after 4 hours of milling. However, there was a decrease in the Portlandite content in parallel with an increase in the density and the surface area.

Strength of mortar containing rubber tire particle

The main focus in this investigation is to determine the strength consist compressive and tensile strength of mortar containing rubber tire particle. In fact, from the previous study, the strength of mortar containing waste rubber tire in mortar has a slightly decreases compare to normal mortar. In this study, rubber tire particle was replacing on volume of fine aggregate with 6%. 9% and 12%. The sample were indicated M0 (0%), M6 (6%), M9 (9%) and M12 (12%). In this study, two different size of sample used with cube 100mm x 100mm x 100mm for compressive strength and 40mm x 40mm x 160mm for flexural strength. Morphology test was conducted by using Scanning electron microscopic (SEM) were done after testing compressive strength test. The concrete sample were cured for day 3, 7 and 28 before testing. Results compressive strength and flexural strength of rubber mortar shown improved compare to normal mortar.

The Effect of Sodium Hydroxide Molarity on Strength Development of Non-Cement Class C Fly Ash Geopolymer Mortar

The use of fly ash as cement replacement material can overcome the environmental issues, especially the global warming problem caused by the greenhouse effect. This is attributed to the CO2 gas produced during the cement manufacturing process, which 1 ton of cement is equivalent to 1 ton CO2. However, the major problem of fly ash is the requirement of activators to activate the polymer reactions. The most common activator used in non-cement or geopolymer material is the combination of sodium hydroxide (NaOH) and sodium silicate. This study aims to identify the effect of NaOH molarity as activator on strength development of non-cement class C fly ash geopolymer mortar. The molarity variations of NaOH were 6 Molar (M), 8M, 10M, 12M, 14M and 15M. The compressive strength test was performed at the age of 3, 7 and 28 days in accordance with ASTM standard, and the specimens were cured at room temperature. The results show that the highest compressive strength was achieved by geopolymer mortar with a molarity of 12M. It exhibits a higher strength to that normal mortar at 28 days. However, the use of NaOH molarity more than 12M tends to decrease the strength of non-cement geopolymer mortar specimens.

Effect of chloride content on mechanical properties of ultra high performance concrete

Experimental results on the effects of chloride content of ultra high performance concrete (UHPC) are presented. The experimental variables are the amount of sodium chloride, ranging from zero to 3.0% per cement weight, and matrix strength, including normal mortar and high strength mortar. Sodium chloride is directly mixed with cement matrix in order to simulate harsh environments by promoting the corrosions of fibers and matrix. The effects of chloride content are evaluated in terms of visual observation, electrical resistivity change, compressive strength, bending strength, and dynamic Young's modulus. The experimental results show that UHPC has the superior capability to resist chloride ions due to its dense microstructures, which prevent the growth of rust crystals. Furthermore, the experimental findings suggest that the potentials for corrosion of steel fibers and for corrosion-induced matrix cracking are inconsequential in UHPC even if chloride ions penetrate into UHPC.

Mechanical Properties of Unsaturated Polyester Resin (UPR)-Mortar and its Potential Application to Restore the Strength and Serviceability of Patched Reinforced Concrete Slab

Degradation of reinforced concrete could occur in various forms including spalling of concrete cover as a result of reinforcement corrosion. The degradation would shorthen the service life of the reinforced concrete structure. Patch repair method may be employed to recover this type of degradation using a suitable patch repair material. The authors have developed a patch repair material made from unsaturated polyester resin (UPR)-mortar. In this paper, the mechanical properties of this material which includes compressive strength, elastic modulus, flexural strength and bond strength are highlighted. Comparisons are also made with the normal mortar to emphasize the superior properties of UPR-mortar. Based on these properties, the potential application of UPR-mortar for repairing damaged reinforced concrete slab is examined through finite element simulation. It is pointed out that the tensile stress intensity in the UPR-layer is reduced with a consequence of reducing a risk of cracking in the repair zone. In addition, the patching of damaged zone with UPR-mortar could minimize the deflection.

Flexural behaviour of bamboo based ferrocement slab panels with flyash

There is a need to develop low cost building elements with the help of locally available materials to fulfil the demand of low cost houses. In rural areas the bamboo, available in abundance, may be utilized as replacement of common M.S. or HYSD bars (a costly building material). Flyash, a by-product from thermal power plants can replace cement in normal mortar or concrete. The flexural behaviour of bamboo based ferrocement slab panels reinforced with chicken wire mesh layers has been studied to improve the serviceability limit. Experimental investigations on simply supported ferrocement slab panels subjected to monotonically increasing uniformly distributed load have been investigated. The experimental programme consists of testing 12 ferrocement slab panels of size 470mm×940mm with the thickness of 40mm and 50mm each having 6 slabs. Out of these slabs, 6 numbers with conventional mortar 1:3 and 6 after 15% cement replacement by fly ash, with adopting grids of bamboo strips as skeletal reinforcement, were cast, cured under wet gunny bags for 28days and then tested under uniformly distributed loading and the test results obtained were compared with the theoretical results. Test results show that the first crack load and the experimental failure load have been found almost same for both types of slabs. The ultimate load has been found to be about doubled the first crack loads. All slabs exhibited large ductility before final failure in flexure.

Thermal Conductivity and Compressive Strength of Lightweight Mortar Utilizing Pumice Breccia as Fine Aggregate

Pumice Breccia is a natural material which is available in a vast deposit of volume in Indonesia, especially in Yogyakarta area. The main characteristics of this type of rock are lightweight and having low thermal conductivity. Pumice breccia utilization is expected to support the implementation of green building concept by minimizing electrical power needs that may be required for setting the room temperature (air conditioning system). The aim of this study is to evaluate the effect of pumice breccia utilization as fine aggregate in various compositions on the thermal conductivity and compressive strength of the mortar. This study conducted using the experimental method to determine the thermal conductivity and compressive strength of each variation of the mortar. Two (2) types of mortar were investigated in this research. The first type is normal mortar using sand as the fine aggregate with mixture compositions variations of 1 Pc (Portland Cement):4 Ns (Sand), 1 Pc:6 Ns, and 1 Pc:8 Ns, which are labeled as MN1, MN2, and MN3. The second type of mortar is pumice breccia mortar that utilizing pumice breccia material as fine aggregate with mixture compositions variations of 1 Pc (Portland Cement):4 Pb (Pumice Breccia), 1 Pc:6 Pb and 1 Pc:8 Pb, named as MP1, MP2, and MP3. All composition of mortar mixtures is prepared based on the volume ratio. Test results show by using the Pumice Breccia as fine aggregate in the mortar mixtures, the thermal conductivity of the normal mortar can be reduced nearly considerably. Even though, the reduction in compressive strength is observed in all the compositions of mortar mixtures, based on SNI 03-6882-2002, still the Pumice Breccia based mortar can be classified into the type-O mortar that can be used for partition walls, protective and decorative purposes.

Valorisation of woody biomass bottom ash in Portland cement: A characterization and hydration study

In the present research work, a characterization of a bottom ash derived from olive plants trimmings combustion was carried out in order to examine its suitability as a substitute in the production of composite cements. For that purpose six different mixtures were prepared: a reference one, containing only ordinary raw materials and five others, substituting Portland cement for 2, 3, 5, 7 and 10wt%. The woody bottom ash (WBA) characterization was carried out by using particle size distribution analysis, chemical analysis and X-ray diffraction (XRD), whereas its microstructure and morphological characteristics were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The physicochemical and mechanical properties of the produced cements mixtures were examined by means of their initial and final setting times, standard consistency, flow of normal mortar, soundness and compressive strength at 1, 2, 7 and 28 days. Their hydration progress was attested by X-ray diffraction, thermogravimetric/differential thermal analysis (TG/DTG), whereas the microstructure of the hardened cement pastes was examined by SEM. According to the results, the WBA could be used as a substitute for Portland cement, in the production of composite cements of the strength classes 42.5 and 32.5 of EN 197-1.

Experimental Analysis of Axially Loaded Aerated Mortar Filled Tubes

This study present, an experimental work on axially loaded aerated mortar filled steel tube in axial compression. The main objective is that to determine maximum load carrying capacity of aerated mortar filled steel tubes and detailed study on the behavior of steel tubes. From the experimental investigation, it was concluded that an empty tube shows concertina mode of failure where as in normalmortar Euler buckling mode failure was observed. It is concluded that Energy absorbing capacity of steel tubes is increased by filling the tubes with aerated/normal mortar and the order of increase is about 64% when filled with aerated mortar and as high as 176% when filled with normal mortar.

Physico-mechanical properties and thermal behavior of firebrick-based mortars in superplasticizer presence

This study presents the effect of the firebrick wastes with high content of Zirconia (HCZ) as fine aggregates by a total replacement of natural sand and/or by partial replacement of cement, on the physico-mechanical and thermal properties of mortars. An experimental study was conducted out to evaluate physico-mechanical and thermal properties of firebrick-based mortars. The natural sand is totally substituted by the firebrick waste as a fine aggregate and also the cement is partially replaced by the firebrick finely ground. The results show firstly that this waste can be upgraded not only mechanically but also thermally. In fact, the microstructural analysis (heating microscopy, TG–DTA and XRD) show that the use of this waste contributes to the formation of multiple phases (corundum, zirconia, quartz, arnite, syn (Ca2SiO4)) whose melting point is considerably higher; this gives the nature of heat-resistant mortars. The introduction of superplasticizer increases in a remarkable way the mechanical strengths compared to normal mortar and waste-based mortars firebricks but is not recommended using superplasticizers at high temperatures. This study allows exploiting these mortars based refractory bricks HCZ up to 1400°C.

PERFORMANCE OF EPOXY RESIN AS SELF-HEALING AGENT

Formation of cracks due to the shrinkage effects during curing and mechanical loading can deteriorate the concrete performance especially in terms of durability aspect. Chemical and harsh solutions will easily penetrate into the concrete and cause damage to the concrete. In order to solve this problem, researchers have introduced a self-healing concrete; the mechanism of automatically repairing concrete cracks without external intervention. Nowadays, the self-healing concrete by using bacteria as a healing agent had gained interest among researchers. In contrast, this paper presents the study on performance of epoxy resin without hardener as a self-healing agent in concrete. Mortar specimens were prepared with mass ratio of 1:3 (cement: fine aggregates), water-cement ratio of 0.48 and 5 to 20% epoxy resin of cement content. All tested specimens were subjected to wet-dry curing; where compressive strength, apparent porosity and self-healing evaluation were measured. Result shows that, the compressive strength of mortar with addition of epoxy resin by 10% increased significantly compared to normal mortar. Epoxy resin as a healing agent was found to be functioned well as the compressive strength and ultrasonic pulse velocity regain the initial reading with prolonged curing time. These results together with microstructure test indicate that epoxy resin can be used as a self-healing agent.

Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings

This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM.

Properties of different particle size of recycled TFT-LCD waste glass powder as a cement concrete binder

In the high-tech industry in Korea, the use of thin-film transistor liquid-crystal display (TFT-LCD) glass products has increased significantly in recent years and large amounts of TFT-LCD waste glass are produced during the manufacturing process. The use of recycled waste glass in Portland cement and concrete has attracted a lot of interest worldwide due to environmental concerns, and the increased cost of disposing of used glass. This research studied the effect of different particle size of grinding TFT-LCD waste glass proportions on binder in cement mortar. Experiments were conducted to determine the optimal replacement content and particle type to ensure that the quality of concrete products is maintained. The results indicate that the use of TFT-LCD waste glass powder as an admixture for cement mortar was efficient in reducing alkali–silica reaction (ASR) expansion and increasing workability. The compressive strength of mortars with TFT-LCD waste glass was also improved compared with that of normal mortar, due to the increased amount of calcium silicate hydrates created by pozzolanic reaction. But it was apparent that the properties of workability, compressive strength and ASR were different significantly with particle size of TFT-LCD waste glass powder.

시멘트계 바탕 바름재용 현무암 석분슬러지 모르타르의 경화 특성

본 연구는 시멘트계 바탕 바름재에 사용되는 바닷모래를 대체하기 위한 재료로서 현무암 가공과정에서 발생되는 현무암 석분슬러지를 재활용하기 위해 현무암 석분슬러지를 사용한 경화모르타르의 특성(연도변화, 응결경화, 흡수계수, 건조수축, 그리고 부착강도 실험)을 평가하였다. 현무암 석분슬러지를 사용한 경화모르타르는 콘크리트 바탕 바름재에 사용되는 기존의 보통모르타르의 특성과 유사하거나 좀 더 향상된 성능을 보였다. 그러나, 현무암 석분슬러지를 사용한 경화모르타르는 보통 모르타르보다 재령 8~9일 이후 건조수축이 증가되었고 부착강도는 감소되었다. 그러나 현무암 석분슬러지를 사용한 경우, KS F 4716 '시멘트계 바탕 바름재'에서 요구하는 최소 품질 규준은 만족하였다. This study aimed to evaluate of the hardened properties (mortar consistency, setting time, absorption properties, drying shrinkage, and bond strength) of the basalt powder sludge mortar recycling a basalt powder sludge occurred during the manufacture process of basalt stone as a replacing material for the sea-sand used to cement filling compound for surface preparation. The hardened mortar made of the basalt powder sludge showed an enhanced performance or similar with the properties of normal mortar used to cement filling compound for surface preparation. But, the drying shrinkage was increased more than a normal cement mortar in the hardened mortar made of the basalt powder sludge since curing 8 - 9days. And the bond strength is low in the hardened mortar used the basalt powder sludge. On the whole, properties of the hardened mortar used the basalt powder sludge correspond to the required minimum quality criterion in the KS F 4716 'cement filling compound for surface preparation'.

Experimental Approach to Enhance the Indirect Split Tensile Strength for Cylindrical and Cubic Specimen for Various Fibrous Mortars under Different Environment Conditions

This experimental investigation was carried out to enhance split tensile strength in various environmental condition which is one of the important harden property of mixed fibrous reinforced mortar. Different fibres like Carbon Fibre,Glass Fibre,Polyester Fibre and Steel Fibre were used in normal mortar and tests were conducted for different proportion (i.e.0%,0.3%, 0.4%,0.6%,0.8% and 1.0%)of fibres to enhance the tensile property of mortar.For this investigation 300 cubes and 300 cylindrical specimens were casted.After the mortar specimen immersion to different types of curing for 28 days and tested after applying direct Alkaline and Acidic curing as well as high temperature effect of 200°C. In this study comparison of various fibrous mortars in different environmental condition checked out.And the strength variation in indirect split tensile strength between Cube and Cylinder were compared. It is observed that polyester fibre 0.4% by weight of cement at 28 days curing gives 46.64% increased Split tensile strength for cube specimen and 31.58% for Cylindrical Specimen. Steel Fibre has good increased split tensile strength of 15.34% for Cube Specimen and 17.32% for Cylindrical Specimen compare to plain mortar in 28 days of acidic curing after the 28 days of Normal curing in tap water and 16.44% for cube specimen and 23.55 % for Cylindrical Specimen compare to plain mortar in 28 days of direct NaCl curing.Carbon Fibre has good increased split tensile strength of 17.54% for Cube Specimen and also 21.04% for Cylindrical Specimen compare to plain mortar under the high temperature effect for 2 hours after the 28 days of Normal curing in tap water. For this research different IS codes and books were referred.

Prediction of Drying Shrinkage Cracking of Eco-efficient Steel Chip Reinforced Cementitious Composite Considering Tensile Creep

This paper reports on the characteristics of drying shrinkage and creep of steel chip reinforced cementitious composite (SCRCC). In this study, first, four restrained wall specimens made of normal mortar and SCRCC with various numbers of steel reinforcing bars (4 or 10) were prepared to compare drying shrinkage characteristics. The specimens were re-strained on the rigid laboratory floor so that shrinkage cracks were induced. The drying shrinkage strains were measured by the contact gauge method and compared with unrestrained small specimens. The number of cracks was simultane-ously observed. Second, bond tests were prepared to evaluate the bond characteristics between the SCRCC and the steel bar. Third, creep tests were performed to improve the accuracy of the analysis of the drying shrinkage behavior. Twelve block specimens were made and a constant flexural load was applied for 7, 14, and 28 days. The observed shrinkage strains and creep strains of SCRCC were modeled according to CEB-FIP Model Code 1990. These models were incor-porated with bond computation between the SCRCC and the steel bar to predict the number of drying shrinkage cracks. The computed equivalent number of cracks based on the shrinkage strain model, the creep model, and the bond model derived from a pull-out test generally agreed with the test results.

Properties of Mortar Containing High Volume Palm Oil Biomass Waste

The utilization of waste materials which are abundant and cheap, especially from clean resources, has become more pressing than ever. This paper, discusses the utilization of the wastes in the form of palm oil fuel ash and oil palm kernel shell in the production of mortar mixes as a part of new and innovative materials in construction industry. The studies include the basic properties including the morphology of the composite with regards to variations in the mix design process. In order to get a better performance in terms of strength development, the ash used has gone through heat treatment and ground up to the size less than 2µm. High volume of 60%, 80% and 100% palm oil fuel ash was used as cement replacement. The incorporation of more than 80% of palm oil biomass waste as cement and sand replacement has produced mortar having an improved compressive strength than normal mortar. In addition, the density of the mortar with biomass waste was less than normal mortar. Overall results have revealed that the inclusion of high volume palm oil biomass waste can produce mortar mix with high strength, good performance and most importantly more sustainable.

Restrained shrinkage behavior of expansive mortar at early ages

The purpose of this study was to qualitatively assess the shrinkage reduction and cracking restraint of expansive additives under various restraint conditions. The reduction of drying and autogenous shrinkages on the addition of expansive additives was confirmed. The results of a ring test performed to determine restrained shrinkage indicated that at the same age, the cracking potential of expansive mortar based on the stress/strength ratio remained lower than that of normal mortar, which confirmed that the generation of compressive stress at an early age reduced the restrained stress and restrained cracking. From the time that cracking occurred, the expansive mortar showed substantial stress relaxation, reducing the tensile stress caused by the interface restraint load. Moreover, the use of expansive additives could reduce the degree of restraint under the same restraint condition, preventing the occurrence of cracking due to shrinkage.

Hydration study of ternary blended cements containing ferronickel slag and natural pozzolan

The present investigation focuses on the hydration evolution of ternary blended cements composed by natural pozzolan (NP) and ferronickel slag (FNS), which is produced during the pyrometallurgical treatment of laterites for the production of ferronickel. The slag and pozzolan were grounded to a specific surface area of 4000cm2/g and twelve different cement mixtures were produced containing up to 20% Portland cement replacement with the above-mentioned cementitious materials. The produced blended cements were tested by determining their initial and final setting times, standard consistency, flow of normal mortar, soundness and compressive strength at 2, 7, 28, 56 and 90days. X-ray diffraction and TG/DTG analyses were used for the determination of the hydration products, whereas the microstructure of the hardened cement pastes and their morphological characteristics were examined by scanning electron microscopy. According to the results, the ferronickel slag could be readily utilized together with natural pozzolan as substitutes for cement, presenting significant environmental benefits in waste management practice.