Termite Mound Soils for Sustainable Production of Bricks

The article presents the alternative use of termite mound soils (TMSs) as full replacement for clay soils in brick production. TMSs from two localities, Jawaj and Sene, in Ethiopia were investigated for bricks production. The TMSs samples contained high SiO2 and Al2O3. The TMSs bricks were fired at different temperatures from 500 to 1,000°C. The obtained mean compressive strengths (σ), 18 and 14 MPa, were observed for bricks made from TMSs from Jawaj and Sene, respectively, at the optimum firing temperature of 700°C. The σ of TMSs bricks decreased as the firing temperature increased above 700°C, while for conventional clay soil brick, the σ increased with temperature beyond 700°C. The water absorptions and saturation coefficients of fired TMSs bricks decreased with increased firing temperature. The TMSs bricks meet the standard specification of dimension tolerance only along the height. All the TMSs bricks made from the two localities were not efflorescent. TMSs from Jawaj and Sene sites can be used as a raw material to replace the long-used clay soils for bricks production as a construction material for houses construction in rural and urban areas.

Effect of multi-layer feeding of sized green pelletson bed permeability, structure and properties of fired pellets in straight grate induration furnace

Green pellets while indurating in a straight grate induration furnace, pass through different thermal treatments, namely drying, preheating, heating and cooling. The firing of the pellet bed is downdraft using Corex gas and cooling is updraft using ambient air. Coke breeze is used as solid fuel to supplies the necessary heat for uniform heating of the pellet. The physicochemical conditions prevailing in the indurating furnace, i.e., feeding rate, bed height, pellet size, position of the pellets in the bed, temperature, partial pressure of oxygen, amount of fuel, etc. have bearings on the phases and structures of the fired pellets across the core to the shell. The time difference between the reduction and oxidation of the pellet depends on the size of the pellet as well as position of the pellet in the bed. The pellet size as well as the position of the pellet in the furnace has a marked effect on the formation of different phases and microstructure. Usually, mixed pellets of different sizes varying from 8 to 16 mm pellets are fired in duration furnace. The study was aimed at to optimize the pellet bed with different size range of pellets put in layers to make uniform firing and cooling of the pellets throughout the bed to achieve desired micro-structure and properties. The green pellets were divided into three sizes as A − coarse (–16 + 12.5 mm), B − medium (–12.5+10 mm) and C − small (–10 + 8 mm). The bed permeability of pellet plant induration furnace was 91.7JPU (Japanese Permeability Unit). Except permeability of pellet bed with single layer of smaller size pellets (C-C-C), the bed permeability with three layers, two layers & single layer of different size pellets was similar or greater than the bed permeability of pellet plant. From the results of basket trials conducted at pellet plant, it was found that the layer wise pellets like B-A-C, CA-B, AB-C and B-B-B resulted in higher Tumbler Index (TI) and Cold Crushing Strength (CCS) compared to other different size pellets as layer due to better slag bonding and lower pellet porosity. These pellets were exposed to optimum firing temperature as well as the cooling process with the presence of sufficient oxygen for the conversion of magnetite to hematite.

Improving the Properties of Clay Soil by Using Literate Soil for Production of Bricks

Know a day’s utilization of local accessible materials is an important stage for sustainable, economic building material on the earth surface. Within them Brick is one of the commonly used construction material around Jimma town due to the availability of clay soil. But brick produced by small micros un-skill enterprises rather than by traditional method, its quantity was small and its quality was unsatisfactory, because it can easily break and it has high water absorbing conduct. The purpose of investigation was be to improving the properties of clay soil properties by using Literate soil for in the manufacturing of bricks for masonry units. In order to achieve this researches include, non-probability sampling techniques was be used to collect samples in Jimma area, then collected of samples prepared for different laboratory test and by partially replacing literate soil by 5%, 10%, 15% and 20% on a clay soil in order to get optimum property by different mix ration for different laboratories. Test results indicated that shows that the lightweight bricks could be made from this study without any deterioration in the quality of bricks. Additionally, the compressive strength of the blocks optimum at 15% lateritic soil replace in clay soil contents. The optimum firing temperature furnace at a duration burning of brick was at 1000°C. It’s shown that bricks prepared of clay-laterite earth capable for high resisting capacity rather than for beauty. Key words: Literate soil, Brick, Clay soil, Compressive strength, Water absorption, sustainable, Density, Construction material.

Effect of type and amount of periclase and dispersing additive type on the properties of vibrocast non­cement periclase siliceous mix and samples from it

Researches have been carried out, as well as a composition and technological parameters for obtaining of vibrocast non­cement periclase siliceous mix and products based on it have been developed. The possibility of using scrap of periclase products along with fused and sintered periclase, the use of which ensures obtaining of high strength properties of samples fired at 1450 C was established. The possibility of using domestically produced powdered quartz as a silica­containing additive, and as dispersing additives: a polymer based on polyethylene glycol; a silica­containing material with a particle size of less than 2 microns and an activity index of hydrogen ions of a 10 % aqueous suspension pH = 6; a chemical phosphate binder was shown. The optimum firing temperature of products (~ 1450 C), as well as the possible application temperature of fired products ( 1580 C), were established. The vibrocast non­cement periclasesiliceous mix and samples from it are characterized, depending on the type of magnesia aggregate and dispersing additive, by the following indicators of physicochemical properties: mass. %: MgO — not less than 86 %, SiO2 — within 6—8 %, Fe2O3 — not more than 1.5 %; grain composition, mm — 6—0; cold crushing strength of samples from this mix after heat treatment at a temperature of 350 and 1450 C is 20—45 and 30—80 N/mm2, respectively; residual dimensional changes during heating (shrinkage) at a temperature of 1580 C (2 h) — not more than 1 %; refractoriness — > 1780 C. The developed vibrocast non­cement periclasesiliceous mix is recommended for vibrocast monolithic linings of high­temperature units of ferrous and non­ferrous metallurgy, cement and other industries, as well as for the manufacture of vibrocast large­sized products and products of complex configuration, both unburnt and burnt.

Improving the Properties of Clay Soil by Using Laterite Soil for Production of Bricks

Nowadays, the utilization of locally accessible materials is a crucial stage for sustainable, economical building material on the earth’s surface. Within them, brick is one of the commonly used construction materials around Jimma town due to the availability of clayed soil. Nevertheless, brick produced by small micros unskilled enterprises rather than by traditional methods, its quantity was small, and its quality was unsatisfactory because it can easily break, and it has high water-absorbing conduct. The purpose of the investigation was to improve the properties of clayed soil properties by using laterite soil for the manufacturing of bricks for masonry units. In order to achieve this, research used non-probability sampling techniques to collect samples in Jimma area. Then, the collected samples prepared for different laboratory tests and by partially replacing literate soil by 5 %, 10 %, 15 % and 20 % on a clayed soil in order to get optimum property by different mix ratio for different laboratory tests results indicated showed that the lightweight bricks could be made from the approach of this study without any deterioration in the quality of bricks.Additionally, the compressive strength of the blocks optimum at 15 % lateritic soil replaces in clayed soil contents. The optimum firing temperature furnace at a duration burning of brick was at 1000 °C for 5hrs. It has shown that bricks prepared of clay-laterite earth capable of high resisting capacity rather than for beauty.

THD Analysis of Novel Envelop with a T type (E-T) Multilevel Inverter with reduced number of switches

Multilevel inverters are a good choice for medium and low power applications. Multilevel inverters have found a wide place in the market for their good power quality output. This paper proposes a new Envelope with T type Novel Multilevel inverter with unequal sources and with reduced switch count. Working of the circuit is explained. Firing angle calculations are done using simple nested looping technique and later Genetic Algorithm is used to obtain optimum firing angles for Selective Harmonic Elimination technique and improve the THD of the output voltage. Comparison is made between different types of inverters. The proposed inverter can be used for speed control of drives

PRODUCING LIGHTWEIGHT CONCRETE AGGREGATE FROM IRAQI ATTAPULGITE

This research aimed to produce a type of lightweight concrete aggregate by using available local materials. The lightweight aggregates were produced using methods of sintered strand produced from Iraqi Attapulgite. Clay particle size, firing temperature, and firing soaking time were selected to determine the effectiveness of these parameters on the relative density of produced aggregate. It was found that decreasing particle size has a negative effect, and the optimum firing temperature is 1100°C for 30 minutes. The unit weight density for LWA obtained is about 808 kg/m3, and the relative density is 1.445.