Experimental Study on Preparation and Performance of Concrete With Large Content of Fly Ash

Producing concrete with large content of fly ash attracts increasing attention in low carbon building materials. In this paper, the fly-ash concrete (FAC) with a content of fly ash no less than 50% total weight of binders was developed. The adaptability of fly ash used for concrete was firstly examined by testing the water requirement of normal consistency and the setting time for cement fly-ash paste, and the strengths of cement fly-ash mortar at the curing age of 7 and 28 days. The factors of water-to-binder ratio from 0.3 to 0.5, the content of fly-ash from 40% to 80%, and the excitation measures with additional Ca(OH)2 and steam curing at initial were considered. After that, the FAC was designed by adding an excessive content of fly ash to reduce the water-to-binder ratio from 0.50 to 0.26, and the content of fly-ash varied from 52% to 60%. Results show that the cement fly-ash paste presented a reduction of water requirement and an elongation of setting time with the increased content of fly ash. This provides a foundation of maintaining the workability of fresh FAC with a decreased water-to-binder ratio by adding the excessive content of fly ash. The cement fly-ash mortar had a lower early strength due to the slow reaction of fly-ash with Ca(OH)2, which could be improved by steam curing at the initial 24 h due to the excitation of fly-ash activity. At curing age of 28 days, the FAC had the expected axial compressive strength and modulus of elasticity, but the tensile strength was lower than predicted. At the curing age of 56 days, all the basic mechanical properties of FAC reached the prediction. The resistances of FAC to chloride ion penetration and carbonization were realized at a very high level as specified in codes.

Water requirement and growth of sorghum over semi-arid region in Deccan Plateau

Based on the result of an experiment conducted from 1978-86 during post-rainy crop season at Solapur, crop coefficients for sorghum during different stages of growth were determined. A model has been developed for relating consumptive use of water at different phenological stages in relation to climatic parameters and crop water needs. The extent to which water requirements of the crop are met and water use efficiency have been discussed. The water requirement appears to be maximum at tasseling/flowering phases of sorghum growth. It works out at 4 mm per day under Solapur environment. The seasonal rainfall in post-rainy season does not appear to furnish a reliable estimate of the yield.

Assessment of Wind and Solar Hybrid Energy for Agricultural Applications in Sudan

In addition to zero-carbon generation, the plummeting cost of renewable energy sources (RES) is enabling the increased use of distributed-generation sources. Although the RES appear to be a cheaper source of energy, without the appropriate design of the RES with a true understanding of the nature of the load, they can be an unreliable and expensive source of energy. Limited research has been aimed at designing small-scale hybrid energy systems for irrigation pumping systems, and these studies did not quantify the water requirement, or in turn the energy required to supply the irrigation water. This paper provides a comprehensive feasibility analysis of an off-grid hybrid renewable energy system for the design of a water-pumping system for irrigation applications in Sudan. A systematic and holistic framework combined with a techno-economic optimization analysis for the planning and design of hybrid renewable energy systems for small-scale irrigation water-pumping systems is presented. Different hybridization cases of solar photovoltaic, wind turbine and battery storage at 12 different sites in Sudan are simulated, evaluated, and compared, considering the crop water requirement for different crops, the borehole depth, and the stochasticity of renewable energy resources. Soil, weather, and climatic data from 12 different sites in Sudan were used for the case studies, with the key aim to find the most robust and reliable solution with the lowest system cost. The results of the case studies suggest that the selection of the system is highly dependent on the cost, the volatility of the wind speed, solar radiation, and the size of the system; at present, hybridization is not the primary option at most of sites, with the exception of two. However, with the reduction in price of wind technology, the possibility of hybrid generation will rise.

Assessment of water requirement of tobacco at Rajamundry (Andhra Pradesh)

Water use, Water Use Efficiency (WUE) and Water Requirement Satisfaction Index (WRSI) oftobacco varieties grown during rabi 1979 to 1988 at Rajamundry had been studied. The yield of tobacco was linearly andsignificantly correlated with amount of rainfall, water use and WRSI. The total amount of rainfall during growing seasonwas inadequate to meet the crop water requirements and these were partially met from stored soil moisture from previouskharif season. The excess rain during ripening stage of tobacco adversely affected the leaf yield and quality.The amount of water consumed varied between 110.0 to 186.6 mm for CTRI Special, 86.8 to 184.0 mm forJayashri. The mean WUE was found to be 6.1 and 6.4 kg/ha/mm respectively for CTRI Special and Jayashri. Themaximum amount of water consumed was 81.2 mm (i.e., 58.7%) during grand growth stage, followed by 36.5 mm(26.5%) during establishment stage and comparatively less (20.6mm) during maturity stage (14.8%). The average Kcvalue was maximum (0.5) during grand growth stage. WRSI showed decreasing trend from sowing towards maturity andthe rate of decrease was high in grand growth stage due to peak water consumption and less rainfall.

Phenophase wise study of parameters controlling water requirement of soybean crop [Glycine max (L.) Merr.] at various agroclimatic zones

Soybean is a major kharif season crop in parts of M.P., U.P., Gujarat, Punjab and Haryana,Maharashtra, Rajasthan, A.P. and Chattisgarh. The present work was undertaken to study the parameters controllingwater requirement of the crop at various phenophases in soybean growing 8 ET- stations (viz., Akola, Bangalore,Banswara, Dharwar, New Delhi, Parbhani, ICRISAT and Rahuri) in various agroclimatic zones. Eight phenophases of thecrop (viz., germination, seedling, vegetative, active vegetative, flowering, pod formation, pod maturity and harvesting)were identified. The data were collected for latest available 3 to 5 years and the mean values were analysed. The study onsoybean crop revealed that the mean total water requirement demand of the crop varied from 294.7 to 559.2 mm indifferent soybean growing ET stations. The ET demand reached the peak mostly at active vegetative stage (which was19.0 to 25.6 % of the total ET demand, at various locations). The computed best – fit ET curves provide ET demand ofthe crop at any point of the phenophases for the specific location. The rainfall during study period was mostly sufficientto meet the crop specific ET demand at various phenophaes of soybean crop. Abundant soil moisture supported goodvegetation cover. The mean Kc value varied widely from 0.61 to 0.98 among different stations studied, which reachedtheir peak mostly at active vegetative to flowering stages, where the values were even more than 1 in most of thosephenophases except 3 stations. The mean soybean crop yield and productivity varied widely agroclimatic zone wise. Thesoybean yield varied from 981.0 kg/ha to 2530.6 kg/ha, while productivity per day varied from 9.0 kg/ha/day to 23.2kg/ha/day. The WUE of the crop laid between 2.1 kg/ha/mm to 6.0 kg/ha /mm at various locations.

A critical study on parameters controlling water requirement or wheat Triticum aestivum L.) at various growth stages in ten different agroclimatic zones

ABSTRACT. The parameters controlling water requirement of wheat and its crop data, at various critical growth stages from ten different agroclimatic zones for five years. were collected and analysed. The study revealed that the total CU-demand for wheat crop in different wheat growing zones varied from 160 to 465 mm of water. In most of the zones, peak CU-demand were either at milk stage (21.0% of the total CU demand or at different stages (19.5% of the total CU-demand). Rabi season rainfall was not sufficient to meet the crop C.U-demand at different growth stages. The soil moisture study revealed that its depletion started around tillering stage indicating thereby, need for irrigation water beyond that stale. Computed average Kc, values (throughout the crop growth period) varied from 0.36 to 1.05 in different agroclimatic zones. Growth stage-wise K, values at or after elongation stage even exceeded one. Wheat yield in various agroclimatic zone varied from 1900 to 4800 kg/ha with the average productivity of 17 to 26 kg/ha/day. The WUE of the crop in different zones lay between 5 to 17 kg of grain/ha/mm of water. Depending upon this study wheat growing areas were divided into six zones.