Experimental study on geopolymer concrete prepared using high-silica RHA incorporating alccofine

Parveen, Parveen,Singhal, Dhirendra,Jindal, Bharat Bhushan Techno-Press 2017 Advances in concrete construction Vol.5 No.4

This paper describes the experimental investigation carried out to develop geopolymer concrete using rice husk ash (RHA) along with alccofine. The study reports the fresh and hardened properties of the geopolymer concrete (GPC) activated using alkaline solution. GPC were prepared using different RHA content (350, 375 and $400kg/m^3$), the molarity of the NaOH (8, 12 and 16M). The specimens were cured at $27^{\circ}C$ and $90^{\circ}C$. GPC was activated using NaOH, $Na_2SiO_3$, and alccofine. Prepared GPC samples were tested for compressive and splitting tensile strengths after 3, 7 and 28 days. RHA was suitable to produce geopolymer concrete. Results indicate that behavior of GPC prepared with RHA is similar to fly ash based GPC. Workability and strength can be improved by incorporating the alccofine. Further, alccofine and heat curing improve the early age properties of the GPC. Heat curing is responsible for the initial polymerization of GPC which leads to high workability and improved mechanical properties of the GPC. High strength can be achieved by using the high concentration alkaline solution in terms of molarity and at elevated heat curing. Further, RHA based geopolymer concrete has tremendous potential as a substitute for ordinary concrete.

Effect of ultra-fine slag on mechanical and permeability properties of Metakaolin-based sustainable geopolymer concrete

Parveen, Parveen,Mehta, Ankur,Saloni, Saloni Techno-Press 2019 Advances in concrete construction Vol.7 No.4

The present study deals with the development of metakaolin-based geopolymer concrete (GPC) and thereafter studying the effects of adding ultra-fine slag on its mechanical and permeability characteristics. The mechanical characteristics including compressive, split tensile, flexural strengths and elastic modulus were studied. In addition, permeability characteristics including water absorption, porosity, sorptivity and chloride permeability were studied up to 90 days. The results showed the effective utilization of metakaolin for the development of elevated temperature cured geopolymer concrete having high 3-day compressive strength of 42.6 MPa. The addition of ultra-fine slag up to 15%, as partial replacement of metakaolin resulted in an increase in strength characteristics. Similar improvement in durability properties was also observed with the inclusion of ultra-fine slag up to 15%. Beyond this optimum content of 15%, further increase in ultra-fine slag content affected the mechanical as well as permeability parameters in a negative way. In addition, the relationship between various properties of GPC was also derived.

Mechanical and microstructural study of rice husk ash geopolymer paste with ultrafine slag

Parveen, Parveen,Jindal, Bharat Bhushan,Junaid, M. Talha,Saloni, Saloni Techno-Press 2019 Advances in concrete construction Vol.8 No.3

This paper presents the mechanical and microstructural properties of the geopolymer paste which was developed by utilizing the industrial by-products, rice husk ash (RHA) and ultra-fine slag. Ultra-fine slag particles with average particle size in the range of 4 to 5 microns. RHA is partially replaced with ultra-fine slag at different levels of 0 to 50%. Sodium silicate to sodium hydroxide ratio of 1.0 and alkaline liquid to binder (AL/B) ratio of 0.60 is taken. Setting time, compressive, flexural strengths were studied up to the age of 90 days with different concentrations of NaOH. The microstructure of the hybrid geopolymer paste was studied by performing the SEM, EDS, and XRD on the broken samples. RHA based geopolymer paste blended with ultrafine slag resulted in high compressive and flexural strengths and increased setting times of the paste. Strength increased with the increase in NaOH concentration at all ages. The ultra-small particles of the slag acted as a micro-filler into the paste and enhanced the properties by improving the CASH, NASH, and CSH. The maximum compressive strength of 70MPa was achieved at 30% slag content with 16M NaOH. The results of XRD, SEM, and EDS at 30% replacement of RHA with ultra-fine slag densified the paste microstructure.

Development of mix design method for geopolymer concrete

Parveen, Parveen,Singhal, Dhirendra Techno-Press 2017 Advances in concrete construction Vol.5 No.4

This study proposes a mix design method for geopolymer concrete (GPC) using low calcium fly ash and alccofine, with the focus on achieving the required compressive strength and workability at heat and ambient curing. Key factors identified and nine mixes with varied fly ash content (350, 375 and $400kg/m^3$) and different molarity (8, 12 and 16M) of NaOH solutions were prepared. The cubes prepared were cured at different temperatures ($27^{\circ}C$, $60^{\circ}C$ and $90^{\circ}C$) and tested for its compressive strength after 3, 7 and 28 days of curing. Fly ash content has been considered as the direct measure of workability and strength. The suggested mix design approach has been verified with the help of the example and targets well the requirements of fresh and hardened concrete.

Transversely isotropic thin circular plate with multi-dual-phase lag heat transfer

Parveen Lata,Iqbal Kaur,Kulvinder Singh 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.3

The present research deals with the multi-dual-phase-lags thermoelasticity theory for thermoelastic behavior of transversely isotropic thermoelastic thin circular plate The Laplace and Hankel transform techniques have been used to find the solution of the problem. The displacement components, stress components, and conductive temperature distribution are computed in the transformed domain with the radial distance and further determined in the physical domain using numerical inversion techniques. The effect of rotation and two temperature are depicted graphically on the resulting quantities.

Effect of nonlocal parameter on nonlocal thermoelastic solid due to inclined load

Parveen Lata,Sukhveer Singh 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.1

The present investigation is concerned with two dimensional deformation in a homogeneous nonlocal thermoelastic solid with two temperature. The nonlocal thermoelastic solid is subjected to inclined load. Laplace and Fourier transforms are used to solve the problem. The bounding surface is subjected to concentrated and distributed sources. The analytical expressions of displacement, stress components, temperature change are obtained in the transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerical simulated results are depicted graphically to show the effect of angle of inclination and nonlocal parameter on the components of displacements, stresses and conductive temperature. Some special cases are also deduced from the present investigation

Thermomechanical interactions in transversely isotropic magneto thermoelastic solid with two temperatures and without energy dissipation

Parveen Lata,Iqbal Kaur 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.6

The purpose of this research paper is to depict the thermomechanical interactions in transversely isotropic magneto thermoelastic solid with two temperatures and without energy dissipation in generalized LS theories of thermoelasticity. The Laplace and Fourier transform techniques have been used to find the solution of the problem. The displacement components, stress components, and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain numerically. The effect of two temperature and relaxation time are depicted graphically on the resulting quantities.

Fractional effect in an orthotropic magneto-thermoelastic rotating solid of type GN-II due to normal force

Parveen Lata,Himanshi 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.4

In this article, we have examined the effect of fractional order parameter in a two-dimensional orthotropic magnetothermoelastic solid in generalized thermoelasticity without energy dissipation with fractional order heat transfer in the context of hall current, rotation and two-temperature due to normal force. Laplace and Fourier transform techniques are used to obtain the solution of the problem. The expressions for displacement components, stress components, current density components and conductive temperature are obtained in transformed domain and then in physical domain by using numerical inversion method. The effect of fractional parameter on all the components has been depicted through graphs. Some special cases are also discussed in the present investigation.

Innovation in Indian Industries: Insights from the First National Innovation Survey

Parveen Arora,Pradosh Nath 아시아기술혁신학회 2015 Asian Journal of Innovation and Policy Vol.4 No.3

Technological innovations, as the key to building competitive advantage, need a comprehensive review to address the issues related to transformation of the Indian industries. The present paper reports the broad findings of the first National Innovation Survey undertaken by the Department of Science and Technology, Government of India. The findings presented here highlight the status of innovation related activities in different industrial sectors, its weaknesses, and areas requiring institutional interventions. The survey results underline the fact that the innovation activities in Indian industries are more for survival in a competitive market conditions than to create market advantage. A sort of disconnect between the innovation support system and the production system is a discernible fact that surfaces from the study. The study also indicates certain characteristics of the innovation behaviour of firms that brings out developing country issues of innovation.

Serum 25-hydroxyvitamin D Insufficiency in B-Chronic Lymphoid Leukemia at the Time of Disease Presentation in Pakistan

Parveen, Saira,Zeeshan, Rozina,Sultan, Sadia,Irfan, Syed Mohammad Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.14

Background: Serum 25-hydroxyvitamin D insufficiency is very common in Pakistan and is often related to inferior prognosis in some cancers but limited data exist for hematopoietic malignancies. This study was conducted to determine the vitamin D insufficiency in B-chronic lymphoid leukemia (CLL) cases at the time of presentation and its possible correlation with clinical staging, hematological parameters and biochemical markers. Materials and Methods: This descriptive cross sectional study was carried at Liaquat National Hospital from January 2011 to June 2013. Sixty patients with B-chronic lymphoid leukemia were enrolled. Complete blood count, vitamin D levels, serum urea, creatinine, uric acid and LDH levels were assessed. Data were compiled and analyzed using SPSS version 21. Results: Out of 60 patients, 42 (70%) were male and 18 (30%) were female. Mean age was $59.0{\pm}9.2years$. The frequency of vitamin D insufficiency was found to be 56.7%. Overall insufficiency was more frequently seen in male gender (40%). Vitamin D insufficiency demonstrated a positive association with low lactate dehydrogenase levels (P=0.005). No links were established with age, clinical stage, hematological and other biochemical markers. Conclusions: Vitamin D insufficiency is high compared with Western studies. Whether normalization of vitamin D insufficiency in deficient B-CLL patients could improve the clinical outcome or delay disease progression will require further studies.