Chemical Properties Of Cement Research Articles

Influence of Diatomite on the properties of mortar and concrete: A Review

Pozzolanic additives set off a fundamental part of high strength and most durable concrete mix design. Pozzolanic materials include natural products such as volcanic product (ashes and pumice) and by-product includes metakaolin, rice husk ash, silica fume, fly ash etc. Diatoms have been utilized as one of the pozzolanic additives in industrial sectors and construction industries to improve the rheological and mechanical properties of cement. Diatomite is sedimentary rocks comprised of amorphous or active silica as its main origin. It is being used very frequently as a pozzolanic additive in cement mortar and concrete. It has manifested appreciable effect in altering mechanical and chemical properties of cement. This paper gives an outlook of the work executed on application of diatomite as partial replacement for Portland cement in mortar and concrete. Different mechanical and rheological properties of cement and concrete containing raw diatomite have been widely discussed in the paper.

Research on Shrinkage Chemical Properties of Cement Stabilized Macadam Material Based on a Multi-dimensional Expansion and Shrinkage Tester

In order to find out the shrinkage law of cement stabilized macadam material under specific conditions, this paper studied the expansion and shrinkage properties of cement stabilized macadam material under two environmental conditions, five kinds of cement dosage conditions, suspended compacted type and skeleton compaced type based on the multi-dimensional expansion and shrinkage tester. Through the test comparison, it is confirmed that the water loss rate of cement stabilized macadam material increases with the increase of cement dosage, showing a general change rule of rising first and then stabilizing. The average increase of the total water loss rate of suspended compacted cement stabilized macadam at room temperature was greater than that of the skeleton compacted cement stabilized macadam. The dry shrinkage strain also follows the above trend. Either at room temperature or under the conditions of dry shrinkage box, the water loss rate of suspended compacted cemeny stabilized macadam is higher than that of skeleton compacted cement stabilized macadam , which can be up to 3.23% higher. By comparing the temperature shrinkage coefficient under the high and low temperature environment, the temperature coefficient of the skeleton compacted cement stabilized macadam is smaller than that of the suspended compacted cement stabilized macadam. The temperature shrinkage coefficient of the suspended compacted cement stabilized macadam increases by 5.56% on average for each 0.5% increase of the cement dosage, and the temperature shrinkage coefficient of the skeleton compacted cement stabilized macadam increases by 6.33% on average. Through the comparative analysis of tests, it can be found that the anti-reflection crack ability of the skeleton compacted cement stabilized macadam material is better, and the fine aggregate content should be strictly controlled in the construction.

Mechanical Properties of Concrete by Replacing Cement with Eggshell powder and Fly ash

This research concentrates on the determination of feasibility of using Eggshell powder and Fly ash as alternate materials of Cement in concrete and their effects on mechanical properties of concrete. The production of cement produces Green house gasses into the atmosphere which pollute the Environment .To overcome this problem we are replacing cement with eggshell powder and fly ash. As the eggshell powder and fly ash are waste material they can available easily and their cost is also very low compared to the production of same amount of cement. The chemical composition of Eggshells is roughly 95% similar to that of cement, which has more calcium content; both physical and chemical properties of cement are almost similar to that of Fly ash. By replacing cement with these two materials in the concrete we can reduce the cost of production of cement and can safeguard the environment. The specimens were prepared and tested for compressive strength, Slump cone test, splitting tensile strength, Modulus of elasticity and flexural strength at 7,14, 28 & 56 days. Results show that the strength of conventional concrete is less than compared to the concrete prepared by replacing the cement with eggshell powder and fly ash.

Effect of SnSO4 on physical and chemical properties of cement

Tin sulfate (SnSO4) can change the setting time and strength of cement due to the presence of sulfate (SO42−), and can reduce the content of hexavalent chromium (Cr6+) in cement owing to its strong reduction ability. This paper studies the influence of stannous sulfate on physical and chemical properties of cement under different temperature and humidity conditions. Adding SnSO4 to the cement mixer resulted in formation of calcium hydroxo-tin, (Sn6O4(OH)4) and CaSn(OH)4. The setting time and strength of cement are obviously enhanced by the addition of stannous sulfate than that of gypsum (CaSO4·2H2O) and stannous chloride (SnCl2), which can be attributed to the coupling of sulfate and stannous ions; Compared with gypsum (CaSO4·2H2O), SnSO4 could hardly produce delayed ettringite (60 days) under hot temperature curing conditions; and water conservation may ensure the full use of stannous sulfate in cement. The total reducing capacity of the SnSO4 on hexavalent chromium (Cr6+) may decrease under hot temperature, but its reduction capacity is still higher than that of ferrous sulfate (FeSO4) under the same conditions. Results from SEM showed that SnSO4 was incorporated into the hydrated cement matrix.

Rice husk as an alternative energy for cement production and its effect on the chemical properties of cement

Production of rice husk in Central Java province is around 2,825,000 tonnes annually. It can be used as an alternative energy source to substitute coal in combustion during cement production. This study was conducted to determine the impact of rice husk as a substitute energy source in cement production. The observations of rice husk comprised calorimetric tests, physical and chemical tests, and percentage rice husk substitution for coal as firing energy. The chemical properties of the cement tested include the chemical content, MgO and SO3 contents, loss on ignition, insoluble residue, and total alkali. The results show that the chemical content of cement which is produced using rice husk as a substitute for coal in the combustion process still meets the Indonesian National Standard.

Parameters controlling early age hydration of cement pastes containing accelerators for sprayed concrete

The objective of this work is to parametrize the early age hydration behavior of accelerated cement pastes based on the chemical properties of cement and accelerators. Eight cements, three alkali-free and one alkaline accelerators were evaluated. Isothermal calorimetry, in situ XRD and SEM imaging were performed to characterize kinetics and mechanisms of hydration and the microstructure development. The reactivity of all accelerators is directly proportional to their aluminum and sulfate concentrations and to the amount and solubility of the setting regulator contained in cement. Alite hydration is enhanced if a proper C3A/SO3 ratio (between 0.67 and 0.90) remains after accelerator addition and if limestone filler is employed, because undersulfated C3A reactions are avoided. Combinations of compatible materials are recommended to enhance the performance of the matrix and to prevent an undesirable hydration behavior and its consequences in mechanical strength development.

Use of Metakaolin as Pozzolanic Material and Partial Replacement with Cement in Concrete (M30)

To achieve sustainability in construction world number of substitutions materials are used. Metakaolin is widely used green pozzolanas. Metakaolin is calcinied clay (koalite). It is obtained from raw material i.e. Kaolin Clay (very fine, white). There is very little emission of carbon dioxide whiles the production of Metakaolin as compared to cement hence it is called as green pozzolanas. The chemical properties of cement were compared with Metakaolin, so that we can replace cement with Metakaolin. In this study partial replacement of cement with Metakaolin at 0%, 3%, 6%, 9% and 12% was done. Mix design was prepared with grade M30 concrete. The compressive strength and split tensile strength of concrete was achieved at 12% addition of Metakaolin. Earlier research also indicate that effect of blended Metakaolin on the properties of cement such as consistency, setting time, soundness remains within the acceptable ranges at different standards. It also solve ecological and environmental problems because cheaper production of Metakaolin and more durable. Therefore this paper provides a scope for more research which is required for green and durable concrete.

Re-use of waste marble dust in the production of cement and concrete

The main objective of this research is to investigate the possibility of utilizing waste marble dust (MD) in cement and concrete production. The research work was divided into two sections. The first section deals with the properties of cement modified with marble dust (marble dust blended cement), whereas the second section discusses the properties of concrete contained marble dust as a cement replacement and as a sand replacement (cement addition). The replacement ratios which have been studied were 0.0%, 5.0%, 7.5%, 10.0% and 15% by weight. Water to powder ratio (w/p) or water to cement ratio (w/c) were 0.50 and 0.40 in case of cement replacement and in case of sand replacement respectively. Physical, mechanical and chemical properties of cement and concrete modified with marble dust were investigated. In addition, TGA, XRD and SEM analysis were performed. Test results of cement paste and cement mortar indicate that the marble dust blended cement remains within the acceptable ranges of the Egyptian standards. Also, generally, the use of marble dust in concrete production as cement replacement or as sand replacement (cement addition) gradually enhances both of the mechanical and physical properties of concrete especially with lower w/c ratio. Marble dust showed a filler effect in concrete and had no noticeable role in the hydration process. Yet, concrete made with marble dust as sand replacement achieved better performance compared to concrete made with marble dust as cement replacement.