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Author: VIRGILUS CHUKWUDI EZUGU

Title: Development of Regressional Models for Predicting Some Mechanical Properties of Sand-Quarry Dust Concrete

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: August, 2016

ABSTRACT

 This research presents regressional models for predicting the compressive strength,
density and slump of sand-quarry dust concrete. The research was prompted by the need to utilize quarry dust, which is a by-product of the quarry industry and presently constitutes environmental menace. The tests conducted included sieve analysis, specific gravity,water absorption, slump, compressive strength and density of the quarry dust concrete.Five component mathematical models based on Scheffe’s simplex method were developed to predict the compressive strength, slump and density of the sand quarry dust concrete.The five components are: Cement, water, sand, quarry dust and crushed rock (chippings).Twenty two different mix ratios were used and each mix ratio contained different percentage replacement of sand with quarry dust. Three samples of each mix proportion were made, giving a total of sixty-six samples. The average of the compressive test results of the three samples of each mix ratio represented the compressive strength of the mix ratio. The average compressive strengths obtained ranged from 30.8N/mm2(corresponding to mix ratio of 1:0.6:2.7:0:3.5) to 44.7N/mm2(corresponding to mix ratio 1:0.5:2:0.4:3.2). The mix ratio refers to the ratio of cement: water:sand: quarry dust:granite chippings by weight. The average density ranged from 2,390.1Kg/m3 to 2,696.3Kg/m3 while the average slump ranged from 9.8mm to 20.8mm.The results from the modal equations using responses from the experimental control points were subjected to statistical analysis including T and F tests and found reliable. The mix with 9.1% quarry dust replacement of sand gave the highest compressive strength of 44.7N/mm2 while the mix with 0% quarry dust gave the minimum strength of 30.8N/mm2. 
 

Author: ANYADIEGWU CHIBUEZE PIUS

Title: Empirical Investigation of the Flexural Strength of Compressed Stabilized Earth Slab

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: August, 2016

ABSTRACT
This research aimed at empirical investigation of flexural strength of compressed stabilized earth slab. Two sets of 500 x 500 x 150mm compressed stabilized earth slabs were cast. One set was cast with BRC mesh of 5 x 150 x 150mm with strength of 250N/mm2 as reinforcement and the other set was cast without reinforcement. Eight mixture proportions of laterite, river sand and cement were used in this research work and optimum moisture content obtained from compaction test of the mixture proportions were used for the casting of the compressed stabilized earth slabs and compressed stabilized earth cubes. Each mixture proportion was used to cast twelve compressed stabilized slabs and six compressed stabilized earth cubes. A total of ninety six compressed stabilized earth slabs and forty eight compressed stabilized earth cubes of 150 x150 x150mm were cast. Comprising 48 reinforced compressed stabilized earth slabs and 48 unreinforced compressed stabilized earth slabs, out of which, 24 of reinforced compressed earth slab and 24 unreinforced compressed earth slab were compressed using 6N/mm2 compaction load while the  remaining equal number of 24 reinforced and unreinforced were respectively compressed with 8N/mm2 compaction load, using Magnus frame. The maximum flexural strength, central deflection and moment obtained using 6N/mm2 compaction load on reinforced compressed stabilized earth slab were  4.74x10-4N/mm2, 3.17x10-3mm and 887.97Nmm  while the corresponding value for unreinforced compressed stabilized  earth slab were 4.06x10-4N/mm2, 2.71x10-3mm and 760.56Nmm. Also, the maximum flexural strength, central deflection and moment obtained using 8N/mm2 compaction load on reinforced compressed stabilized earth slab were 5.50-4N/mm2, 3.68x10-3mm and 1030.8Nmm while the corresponding value for unreinforced compressed stabilized earth slab were 4.53x104N/mm2,3.03x10-3mm and 849.36Nmm. From this research, it can be concluded that reinforced compressed stabilized earth slabs with high compaction load have high flexural strength, central deflection and moment when compare with unreinforced compressed stabilized earth slabs. 
  

Author: ANYANWU, VENATIUS KOSISOCHUKWU

Title:  Reliability Studies of Six Evapotranspiration
Models for Three Selected Towns in South-Eastern Nigeria

Affiliation: Agricultural Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: February, 2016

ABSTRACT
Penman modified, Priestly Taylor, Blaney-Morrin Nigeria, Jensen-Haise, Hargreaves-Samani and Thornthwaite models were used to estimate Reference Evapotranspiration (RET) in three selected sites in South-Eastern Nigeria namely: Awka, Enugu and Owerri from 1990 to 2010.The Penman modified model was chosen as a comparison for evaluating the other five empirical models. Good correlation was predicted between the RET values estimated by each of the five radiation and temperature based and the Penman modified model, although there were some discrepancies. The mean annual RET estimated by the Penman modified method as the standard tool for Awka, Enugu and Owerri were found to be 1109.2, 997.4 and 1045.0mm respectively.  Conversely, from the mean monthly RET estimated results, Awka was highest followed by Owerri and Enugu was lowest. This is due to the valley and hilly terrain of the station. The best RET estimate for Awka station was given by Blaney-Morrin Nigeria model, followed by Thornthwaites for Enugu and Thornthwaite for Owerri stations. In regression statistical analysis, PriestlyTaylor (PT)   consistently had the highest T-scores and lowest RMSE for Awka and Owerri stations while Jensen-Haise had the highest T-scores and smallest Root Mean Square Error (RMSE) by Thornthwaite for Enugu station.The Penman modified model estimates were used to develop correction factors for the three models) that predicted best in each station for their potential use. The three best models are : Awka(BMN,HS and TH),Enugu(TH,HS and BMN) and Owerri(TH,BMN and HS) respectively. Priestly Taylor and Jensen –Haise deviated for particular stations were based on the fact that they are radiation based models. 

Author: STANLEY OGADINMA AMADI

Title: Investigation of Flexural Strengths of Concretes Containing Rice Husk and Saw Dust Ashes From Different Calcination Methods

Affiliation: Civil Engineering Department
School of Engineering and Engineering Technology
Federal University of Technology, Owerri Imo State

Date: July, 2016

ABSTRACT
This work investigated the flexural strengths of concretes containing rice husk ash (RHA) and saw dust ash (SDA) from different calcination methods. RHA and SDA were produced using three different calcination methods namely, Open-Air (OA), Furnace (F), and Stove (S). Each of RHA and SDA was used as partial replacement of Ordinary Portland Cement (OPC) at 5%, 10% and 15%. 171 concrete beams of dimensions 150 x 150 x 600mm were produced using 1:2:4 cement–sand–sandstone mix ratio and 0.6 water/cement ratio. This comprised 81 OPC– RHA, 81 OPC–SDA and 9 OPC (control) concrete beams. The beams were cured by immersion and tested for flexural strengths at 28, 90 and 150 days. The results showed that the flexural strength of the blended cement concrete increased with curing age and decreased with increased amount of RHA and SDA. The 150th day flexural strengths for 5% RHA were 5.35 Nmm-2 for OA, 6.74 Nmm-2 for F and 5.20 Nmm-2 for S. Corresponding strengths at 5% SDA were 4.48 Nmm-2 for OA, 5.85 Nmm-2 for F, and 4.28 Nmm-2 for S, while the Control value was 6.41 Nmm-2. Thus, for 5% replacement of OPC with RHA, OA calcination had 83.5% the strength of the control; F calcination had 105.1% the strength of the control, while S calcination had 81.1% the strength of the control. Similarly, for 5% replacement of OPC with SDA, OA calcination had 69.7% the strength of the control; F calcination had 91.3% the strength of the control, while S calcination had 66.7% the strength of the control. Therefore, although furnace calcination gave higher strength than open-air and stove calcinations, the latter two could still be used for structural members with lower flexural strength.  

Author: NWACHUKWU, OGECHI MERCY

Title:  Characterization, Classification, and Evaluation of Soils of Four Geomorphic Surfaces in Oguta Imo State Southeastern Nigeria

Affiliation: Soil Science Technology  Department
 School of Agriculture and Agricultural Technology
 Federal University of Technology, Owerri Imo State

Date: June, 2016

ABSTRACT
This research was carried out to characterize, classify, and evaluate soils of four geomorphic units in Oguta Imo State Southeastern Nigeria. Four Pedons, each was located in each geomorphic unit. ] soil sampling was carried out in the study site, sixteen surface soil samples (0-20 cm) were collected, four from each of the geomorphic units using an auger giving a total of thirty three soil samples which was chosen to represent the main morphological variations and to present mapping units throughout the soils of Oguta Imo state Southeastern Nigeria. Results of the laboratory analysis showed that the soils were predominantly sandy loam and loamy sand. Texture was coarser at the terrace than the levees and backswamp. The soils in the levee crest, were classified into subgroup Typic Eutrudepts, levee slope and terrace Typic Hapludults while soils of backswamp were classified as Typic Endoaquepts. The soils were classified into land capability class II, III, IV and V with limitations due to nutrient holding capacity (n), wetness, (w) and angle of slope (a). The results of the land suitability classification for wetland rice production showed low suitability (S3) for all the soils. Land suitability classification for cassava production showed moderate or medium suitability (S2) for the soils of levee crest, levee slope and terrace, while the soil of backswamp has low suitability (S3). However, soils of levee crest – backswamp (EO1EO4), levee crest surface soils - terrace surface (EO1S-EO3S) showed moderate or medium suitability (S2) for maize production while backswamp surface soils (EO4S) showed low suitability for maize production. Land suitability classification for Sugarcane production showed moderate/medium suitability (S2) for all the soils in the studied geomorphic units. Data generated from various analyses were subjected to analysis of variance (ANOVA). Correlation analysis was used to estimate degree of relationship among soil properties. The results of fertility capability classification (FCC) showed uniform loamy top and subsoil. The major limitations of the soils for crop production are soil texture and structure, which directly affect waterholding capacity, permeability of the soil among other soil physical properties.