Rich Cement Research Articles

Sustainable solutions for Workable and Strong concrete: Cordia Gel and Waste Engine Oil Admixtures

To produce high strength or rich cement concrete having low water to cement ratio with adequate workability is the biggest challenge for the construction industry. To achieve the necessary workability, the world is now using costly chemical admixtures. Research should be carried out to explore materials having potential to be utilized as costeffective chemical admixtures in concrete. The primary goal of this research is to investigate the combined effect of Cordia Gel (CG) and Waste Engine Oil (WEO) as chemical admixtures on fresh and hardened properties of concrete. Fresh properties of concrete were examined in terms of workability and hardened properties were investigated by compressive strength test and Ultrasonic Pulse Velocity (UPV) test on cubical specimen of dimensions 100mm x 100mm x 100mm after 7, 28 and 90 days of curing in water. Four different percentages of WEO (0.5%, 1%, 1.5% and 2%) were used and percentage of CG kept constant as 0.5% with respect to weight of cement and results were compared with the control mix. Results revealed that workability of fresh concrete increased with increasing amount of CG and WEO. However, a decreasing trend was observed for compressive strength and UPV of hardened concrete when higher values of admixtures were added. The usage of CG and WEO as chemical admixtures in concrete can be a sustainable and cost-effective way to achieve the desired results

Ecological engineering of iron ore tailings into useable soils for sustainable rehabilitation

Ecological engineering of soil formation in tailings is an emerging technology toward sustainable rehabilitation of iron (Fe) ore tailings landscapes worldwide, which requires the formation of well-organized and stable soil aggregates in finely textured tailings. Here, we demonstrate an approach using microbial and rhizosphere processes to progressively drive aggregate formation and development in Fe ore tailings. The aggregates were initially formed through the agglomeration of mineral particles by organic cements derived from microbial decomposition of exogenous organic matter. The aggregate stability was consolidated by colloidal nanosized Fe(III)-Si minerals formed during Fe-bearing primary mineral weathering driven by rhizosphere biogeochemical processes of pioneer plants. From these findings, we proposed a conceptual model for progressive aggregate structure development in the tailings with Fe(III)-Si rich cements as core nuclei. This renewable resource dependent eco-engineering approach opens a sustainable pathway to achieve resilient tailings rehabilitation without resorting to excavating natural soil resources.

Effects of thermal treatment on the mechanical properties, microstructure and phase composition of an Ettringite rich cement

Recently calcium sulfoaluminate cements gain increasing attention due to their significant potential to reduce the carbon footprint of cement production compared to Portland cement. However, the conditions applied during its processing play a crucial role for the stability and longevity of the material. Thereby, the temperature has a decisive influence, as it is already known from numerous studies that ettringite structurally changes significantly upon thermal induced dehydration. Within this background, the present study subjects a holistic view of the mechanical, morphological, phase and structural changes of a commercial calcium sulfoaluminate cement related to the dehydration of the contained ettringite upon treatment at drying temperatures from 23 °C to 100 °C for 7 and 28 days. By complementary methods it is shown that with increasing curing temperature, the mechanical stability decreases, the total pore area and porosity increase, while the permeability of the microstructure is lower for samples stored at 100 °C. Removal of water increases the intercolumnar distance within the ettringite lattice, thereby inducing strain which is released upon rehydration. Although during storing at a temperature of 100 °C ettringite is transformed into an X-ray amorphous product, the initial morphology of the crystals embedded in the cementitious matrix is retained.

Performance of imported granulated blast-furnace slag (IGBFS) rich cement against fire resistance

Performance of imported granulated blast-furnace slag (IGBFS) rich cement against fire resistance

Analysis of hydration products, hydration degree, and CO2 capture in “ye'elimite –H2O” system by X-ray diffraction, combined SEM-EDS, and FTIR techniques

By application of the XRD, combined SEM-EDS, and FTIR techniques, this study analyzes morphology, chemical elemental composition, and carbonation of the hydration products precipitated in “ye'elimite–H2O” system. The hydration experiment was conducted at a w/y ratio by weight of 3 and a long hydration time of 270 days and resulted in precipitation of the ettringite, gibbsite, and calcite. The hydration degree (≈ 85%), the actual amount of the captured CO2 (≈ 0.14g/g), and the maximum CO2 capture capacity (≈ 0.22g/g) of the ye'elimite as a result of the hydration process are evaluated on the bases of a combined analysis of the proposed net hydration reaction and recorded SEM-EDS data. The uptake of CO2 by hydrated ye'elimite is contributed by calcite and carbonated ettringite. The data of SEM-EDS measurements are also used for confirmation of the mechanism proposed in literature for explanation of the retardation of the ye'elimite hydration by the gibbsite. The results reported in this study may be useful (i) in terms of analysis of the hydration products that are formed as a result of hydration of the ye'elimite and commercial ye'elimite-rich cements and (ii) for quantitative analysis of the captured CO2 by hydrated ye'elimite and ye'elimite-rich cements.

Retrofitting techniques of damaged concrete structure for environment concern: A review

Initiation and progression of damages in the concrete systems is the cause of reduction of structural strength and its durability. The significant retrofitting strategies are required to improve the damages and thus, the performance of infrastructures can be enhanced. The damages in the concrete system is due to several factors viz., ingress of alkaline water, wet-dry cycle, sulfate attack, thermal changes, chloride penetration, and freeze–thaw cycle etc. Changes in the shape and size of concrete segments before and after retrofitting decreases the strength of structural systems and consequently, reduced the durability of retrofitted materials. This review paper is motivated on the application of the retrofitting techniques using Fiber Reinforced Polymer (FRP) material for environment concerned. The deterioration of concrete structure and FRP retrofitted materials durability were discussed. The durability aspect of damaged concrete structure retrofitted with FRP materials under alkaline water, wet-dry cycle, freeze–thaw cycle, open cracks, and water immersion were reviewed. The de-bonding of FRP materials have been described to improve the structural integrity. The suitability of various retrofitting techniques were covered. This paper have been included the retrofitting techniques for the improvement of infrastructural facilities and further, the cracks filled rich cement mortar with FRP over that was the key finding. The review paper will facilitate innovative research directions to the industrialist and researchers.

Effects of Thermal Treatment on the Mechanical Properties, Microstructure and Phase Composition of an Ettringite Rich Cement

Effects of Thermal Treatment on the Mechanical Properties, Microstructure and Phase Composition of an Ettringite Rich Cement

EFFECT OF USING GEOPOLYMER MORTAR IN FERROCEMENT BY VARYING THE COMBINATION, NUMBER AND SIZES OF MESHES

Globally, Cement production contributes about 1.6 billion tons of CO2 or about 7% of global loading of CO2 into the atmosphere. The manufacture of Cement Releases Carbon dioxide that is significant contributor of Green house gas emissions to the atmosphere. So there was a need to develope and use eco-friendly material having similar properties as like of cement mortar. Geopolymer is produced without the presence of cement as a binder; instead, the base material such as fly ash, that is rich in Silicon (Si) and Aluminium (Al), is activated by alkaline solution to produce the binder. Hence Geopolymer mortar can be used instead of cement mortar which will have no adverse effect on our environment. Ferrocement is a composite material formed by closely spaced wire mesh which uses wire meshes as reinforcement and filled with rich cement mortar. Experimental investigation was carried out to study the effect of Geopolymer mortar in Ferrocement for variation in mesh size and number of layers. For this, tensile testing was done on Geo-ferrocement specimens of size 750 x 60 x 30 mm reinforced with single, double, triple layer using variation in meshes of different sizes. Similarly, compression testing of cubical specimens of side 70 mm reinforced with single, double, triple layer of meshes sizes was done. Results indicated an significant increase in tensile strength and compressive strength of specimens with increase in number of layer of meshes. Test results also provided the most suitable combination and size of mesh to be used for obtaining the maximum strength of different sizes was done.

Surface Properties of Cement Kiln Dust with Water Treatment for Selective Extraction of Calcium and Potassium.

Water and hydrochloric acid were employed as solvents to extract K and Ca from K- and Ca- rich cement kiln dust (CKD). It has been shown that hydrochloric acid effectively extracts Ca and K from CKD with efficiencies of more than 85 and 99%, respectively. On the other hand, water, as a solvent, selectively extracts K and Cl with an efficiency of 99%. The selectivity of Ca extracted using hydrochloric acid from treated CKD increased from 37 to 87%. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that K and Cl were dominant on the surface of fresh CKD. After extraction with water, the portion of Ca increased more than twice, and Ca species became dominant. Thus, extraction of CKD with water is capable of selectively removing KCl, leaving Ca on the surface; hence, treated Ca-rich CKD can serve as a suitable raw material for mineral carbonation.

Influence of fly ash on the volumetric and physical properties of Stone Matrix Asphalt Concrete

Stone Matrix Asphalt (SMA) is a gap-graded asphalt concrete hot blend combining high-quality coarse aggregate with a rich asphalt cement content. This blend generates a stable paving combination with a powerful stone-on-stone skeleton that offers excellent durability and routing strength. The objectives of this work are: Studying the durability performance of stone matrix asphalt (SMA) mixture in terms of moisture damage and temperature susceptibility and Discovering the effect of stabilized additive (Fly Ash ) on the performance of stone matrix asphalt (SMA) mixture. In this investigation, the durability of stone matrix asphalt concrete was assessed in terms of temperature susceptibility, resistance to moisture damage, and sensitivity to the variation in asphalt content. Specimens of 63.5 mm height and 102 mm diameter were compacted using the Marshall method at 150 °C. The optimum asphalt content was determined. Additional specimens were prepared with (0.5) percent below and above the OAC requirement. Specimens were subjected to indirect tensile strength (ITS) determination at (25 and 40) °C, and double punch shear strength determination. Another group of specimens was subjected to Marshall properties determination and to moisture damage. It was observed that stone matrix asphalt exhibit lower sensitivity to the change in asphalt content from the resistance to moisture damage and temperature susceptibility points of view. However, the tensile and shear properties exhibit significant sensitivity to the variation in asphalt content.

Experimental investigation on different high rich cement mortar for ferrocement application

Abstract Nowadays the Laboratory research became assumed to enlarge high rich cementitious matrices for casting thin ferrocement laminates perfectly fitted for structural restore retrofit. The developed high rich mortar matrices contain diverse combos of silica fume and Metakaolin, and offer a great balance among flowability and rich. The matrices evolved have a 28-days compressive rich variety from 48 to 64 MPa with an equivalent float range from 129% to 138%. The different high rich mortar turned into used in generating ferrocement jackets for cylindrical stubs look at its performance of the stubs are subjected to axial stresses. The progressive excessive rich ferrocement laminates seem to provide the considerable increase and increasing in the load carrying potential, lateral and ductility. In positions of ferrocement efficiency, the stubs enveloped with the laminates containing 2 and 4 layers of welded wire meshes (WWM), presented approximately 61% and 31% increase in axial stress respectively, with a corresponding increase in axial stress of about 33% and 71% respectively. Based on the outcomes of the present research, high rich ferrocement laminates containing a particular variety of welded wire meshes may be taken into consideration as a promising material for maintenance and recovery of concrete structures, particularly when using flowable high rich mortar with WWM complying with ferrocement specifications.

Rheological properties of belite-rich cement doped with sulfur

Reactive belite cement based on clinker doped with sulfur is a new type of low-energy cement that is still in the laboratory testing phase. In terms of application, one of the desired properties of new cement is its well-defined rheological behavior in fresh state. The chemical composition of the belite cement was determined by wet chemistry analysis, the phase composition of the belite cement clinker by quantitative X-ray powder diffraction analysis and microscopic point counting and specific surface by Blaine method. Rheological properties were determined by rotational rheometer in flow and oscillation regime. Shear and time dependent rheological parameters were calculated from flow curves. Stability of belite cement paste was judged based on the critical strain determination in amplitude sweep test. Setting was evaluated by Tussenbrock needle penetration test and oscillation time test on rheometer. The properties of the laboratory belite cement were correlated to industrial cement CEM I, CEM II/A-LL and CEM III/A. Reactive belite cement pastes show good flow properties both due to small amount of alite and larger amount of rounded belite grains and clusters. Belite rich cement show decent stability comparable to CEM III and very good dispersing efficiency of PCE based HRWR.

Study on the Influence of Minor Constituents in Blast Furnace Slag Rich Cement on the Thermal and Mechanical Properties of Concrete

Study on the Influence of Minor Constituents in Blast Furnace Slag Rich Cement on the Thermal and Mechanical Properties of Concrete

Some microstructure properties at early age of ettringite binder based on rich C12A7 calcium aluminate cement

The mineral composition of calcium aluminate cements is traditionally based on CA (monocalcium aluminate-CaO·Al2O3). Recently, a new cement with the main compound of C12A7 (Mayenite) has been developed for rapid hardening binder. This cement is used in conjunction with a sulfate binder to form a new type binder called ettringite binder due to the high quantity of ettringite in the hydration product, opened new possibilities for mortar and concrete formulations. This paper focuses on some microstructure characteristics of the ettringite binder based on a C12A7 rich cement and a hemihydrate at early age. Some important characteristics of this binder were found, such as: short setting time (about 40–50 minutes), rapid expansion just after initial setting time, rapid evolution of porosity and bound water during the first 5 hours of hydration. The correlation between bound water and porosity of hardened binders was also found in this paper.
 Article history: Received 24 January 2018, Revised 04 April 2018, Accepted 27 April 2018

Valorization of glass and shell powders in the synthesis of Belitic clinker

In recent years, waste recycling has become a key issue in construction materials science for achieve the goal of sources of raw materials. The aim of this study is to use waste glass as source of SiO2 oxide and mussel shells consisting essentially of calcium carbonate as starting materials to synthesize belite rich cement. The elaborated clinker is chemically and structurally related to β-Ca2SiO4, by heat solid state activation. After grinding, the raw materials are mixed and heated up to 1050°C. The samples are characterized by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FT-IR). The mechanical strength of some sample was measured for 28 and 72 days. The results show the different mineralogical stapes of formation of clinker, the state reaction method allows the elaboration of a cementitious material by a simple heat treatment at relatively low temperature and low release of CO2. The hydration products are also identified by XR diffraction at 2, 7, 28 and 72 days.

Valorization of glass and shell powders in the synthesis of Belitic clinker

In recent years, waste recycling has become a key issue in construction materials science for achieve the goal of sources of raw materials. The aim of this study is to use waste glass as source of SiO2 oxide and mussel shells consisting essentially of calcium carbonate as starting materials to synthesize belite rich cement. The elaborated clinker is chemically and structurally related to β-Ca2SiO4, by heat solid state activation. After grinding, the raw materials are mixed and heated up to 1050°C. The samples are characterized by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FT-IR). The mechanical strength of some sample was measured for 28 and 72 days. The results show the different mineralogical stapes of formation of clinker, the state reaction method allows the elaboration of a cementitious material by a simple heat treatment at relatively low temperature and low release of CO2. The hydration products are also identified by XR diffraction at 2, 7, 28 and 72 days.

Phase assemblage in ettringite-forming cement pastes: A X-ray diffraction and thermal analysis characterization

The study attempts to describe the evolution of the solid phase composition with ongoing hydration in three different calcium aluminate rich cement paste mixtures by means of XRD and thermal analysis. The phase assemblage was followed quantitatively at discrete ages of 1, 7, 28, 56 and 90 days. Ettringite was the main crystalline hydration product. Quantification of amorphous fractions using the external standard method was performed and relatively high amounts of amorphous fractions were reported in all the cases.Thermal analysis revealed that the X-ray amorphous hydrate fraction was mainly composed of monosulphate, AH3 and C-S-H. The presence of strätlingite, was not clearly manifested in any of the DTG curves. A mass balance calculation based on stoichiometric reactions was performed in order to estimate the amounts of monosulphate, AH3, and C-S-H. The quantities of the amorphous portions obtained from QXRD were observed to be higher as those estimated from mass balance calculations. Additional calculations from oxide balance suggested that besides AH3 monosulphate and C-S-H, an X-ray amorphous AFm or/and C-S-H type like phase might form in the early age of hydration.During Rietveld refinement, the impact of the number of Chebyshev background polynomials in the determination of amorphous content was investigated.

Physicochemical Characteristics of Slag Rich Cement Pastes Incorporated by-pass Cement Dust

Physicochemical Characteristics of Slag Rich Cement Pastes Incorporated by-pass Cement Dust

Dynamical behaviors of structural, constrained and free water in calcium- and magnesium-silicate-hydrate gels

HypothesisThe mechanical properties of cement pastes depend strongly on their porosities. In a saturated paste, the porosity links to the free water volume after hydration. Structural water, constrained water, and free water have different dynamical behavior. Hence, it should be possible to extract information on pore system by exploiting the water dynamics. ExperimentsWe investigated the slow dynamics of hydration water confined in calcium- and magnesium-silicate-hydrate (C-S-H and M-S-H) gels using high-resolution quasi-elastic neutron scattering (QENS) technique. C-S-H and M-S-H are the chemical binders present in calcium rich and magnesium rich cements. We measured three M-S-H samples: pure M-S-H, M-S-H with aluminum-silicate nanotubes (ASN), and M-S-H with carboxyl group functionalized ASN (ASN-COOH). A C-S-H sample with the same water content (i.e. 0.3) is also studied for comparison. FindingsStructural water in the gels contributes to the elastic component of the QENS spectrum, while constrained water and free water contribute the quasi-elastic component. The quantitative analysis suggests that the three components vary for different samples and indicate the variance in the system porosity, which controls the mechanical properties of cement pastes.

The Effect of High Temperatures on the Mechanical Properties of Concrete with Different Strengths at Different Mixing Ratio

This research work includes an experimental study of the mechanical properties , as compressive strength, tensile strength, modulus of elasticity, and stress – strain relation for ordinary concrete. Different mixes of different cement content and W/C ratio considered at different high temperature. Nine different concrete mixes for different cement content and W/C ratio are exposed to four steps of high temperature (20, 200, 400, 600)°C for a duration of one hour. The results show that heating the concrete samples reduces the mechanical properties of the samples in a different percent for different mixes. The affect of high temperatures to modulus of elasticity , splitting tensile strength and compressive strength for concrete are different and various. It has been found that the concrete mixes of low strengths (a few cement and high W/C ratio) maintains compressive strength more than concrete mixes which have high strength (rich cement and low W/C ratio) when exposed to high temperatures. This effects generally vary from mix to another in some or all properties. In general there are less effect at (200°C) degree, then the changes become more sensitive at higher temperature ( 400, 600)°C.