Refreed Journals

This paper presents the study of physico-chemical parameters of Lake Bosomtwe to determine whether the water from the lake is suitable for irrigation and future planning of clean water resources. Water quality parameters like temperature, pH, TDS, SAR, SSP, RSC, KR and other trace elements were investigated. The study was carried out in the month of February, 2014. Water from 10 sampling locations wasanalyzed and the results compared with international water quality standards set for irrigation. All the parameters were found outside the permissible limit apart from temperature, EC and TDS. On the basis of this, itisno surprisedthat the lake water is not used for irrigation

The paper presents results of a study on concrete mixes containing two types of calcined clay pozzolanas obtained
from Mankranso and Tanoso for structural application. Mankranso sample is labeled Type I whilst Tanoso also labeled as type II.Both clay samples were analysed to determine their physical and geotechnical properties whilst the chemical composition of the calcined clay samples analysed. Portland cement was replaced with 0%-25%Type I and 0-30% of Type II pozzolanas to formulate binder pastes and concretes. Setting times and normal consistency test were determined on the formulated binder paste. Three grades of concrete (25N/mm2, 30N/mm2 and 40N/mm2) containing pozzolana were prepared and their workability, density, compressive strength and flexural strength investigated against the plain concrete. Concretes with clay pozzolana had delayed setting times and lower densities. They also exhibited a reduction in compressive and tensile strength development at early age (7 days), with an average drop of 6 percent in compressive strength for all grades. However, the compressive and tensile strengths beyond 28 days notably exceeded the control un-blended mixes. This study recommends up to 20% clay pozzolana content of both Types I and II for concrete grades of 25N/mm2, 30N/mm2 and 40N/mm2.

The performance of Portland cement in concrete or mortar formation is very well influenced by chemical compositions amongother factors. Many engineers usually have little information on the chemical compositions of cement in making decisions for thechoice of commercially available Portland cement in Ghana. This work analyzed five different brands of Portland cement in Ghana,namely, Ghacem ordinary Portland cement (OPC) and Portland limestone cement (PLC), CSIR-BRRI Pozzomix, Dangote OPC, andDiamond PLC. The chemical compositions were analyzed with X-Ray Fluorescence (XRF) spectrometer. Student’s?-test was used totest the significance of the variation in chemical composition between standard literature values and each of the commercial cementbrands. Analysis of variance (ANOVA) was also used to establish the extent of variations between chemical compositions andbrand name of the all commercial Portland cement brands. Student’s?-test results showed that there were no significant differencesbetween standard chemical composition values and that of commercial Portland cement. The ANOVA results also indicated thateach brand of commercial Portland cement varies in terms of chemical composition; however, the specific brands of cement hadno significant differences. The study recommended that using any brand of cement in Ghana was good for any construction worksbe it concrete or mortar formation

Portland cement is an important commodity in almost every part of the world. Its importance is visible in the construction and concrete industry which are very pivotal in the growth of major economies. In Ghana the construction industry is among the pillars the drives the economy. This study attempted to investigate the impact of some selected macroeconomic indicators on the performance of cement prices between the period of 2000 and 2014. The macroeconomic indicators studied were inflation rate, monetary policy rate and exchange rate. The study used multiple linear regression analysis for the interpretation of the inferential statistical data. The regression results showed that cement cost was not responsive to the trends in inflation and monetary policy rates. It was however responsive to trends in the exchange rate pattern showing a positive relation. To effectively control cement prices, the study recommends an effort to use local materials such as burnt bricks and calcined clay pozzolan which don’t need so much of foreign exchange for any form of importation

Curing of cement based products such as concrete and mortar, is very important to achieve good strength and durable products. However the curing environment plays a pivotal role in the overall quality of cement based products in terms of strength development. ASTM C192 allows moist cur-ing either in a fog room or under water. However, these must meet ASTM C511 which controls temperature, and specifically for water curing, the concentration of calcium ions in the curing so-lution. Unfortunately in many parts of the world, water curing literally means curing in tap water. This is done primarily because there is a lack of knowledge or ignorance regarding the mobility and roll of calcium hydroxide in the curing process. To illustrate the differences, in this study, straight ASTM Type I/II Portland cement and that mixed with powdered waste clay bricks as a cement extender were used to prepare two different batches of mortars. The chemical properties of the powdered waste clay brick met the ASTM C618 standard specifications for Class N pozzolans. Both mortar specimens were cured under two different environment comprising of either water and lime saturated water. Mortar specimens were tested for compressive strength at 3, 7, 14 and 28 days of either curing conditions. Test results indicated that mortar specimens cured in lime saturated water obtained higher strength than those cured in fresh water at all ages of curing. Sta-tistical inference drawn from ANOVA testing showed that curing conditions had significant impact on strength development of the blended and unblended cement systems. The study recommends that testing of concrete and mortar samples and other research related works be performed in lime saturated water other than fresh water