Effect of Salt Water in the Production of Concrete

In this research work, the effect of salt water in the production of concrete was investigated. A total of ninety (90) concrete cubes were cast for compression strength test i.e. forty five cubes were cast using fresh water and the other forty five cubes were also cast using salt water. Similarly, a total of ninety (90) concrete beams were cast for flexural strength test i.e. forty five beams were cast using fresh water and the other forty five beams were also cast using salt water. The concrete cubes and the beams were cured at 7,21,28,60 and 90 days respectively. The result of the average compressive strength of concrete obtained using fresh water  of mix ratio (1:1.51:4.01), water cement ratio (0.47) ranges from 27.35-42.34N/mm2 while that of salt water ranges from 25.24-38.81N/mm2 for the hydration period of 7,21,28,60 and 90 days. The flexural strength of concrete obtained using fresh water of the same mix ratio and water cement ratio ranges from 6.60 – 11.20N/mm2 for 7,21,28,60 and 90 days hydration period while that of salt water ranges from 5.98-11.04N/mm2 for the same hydration period. For the mix ratio (1:1.61:4.03) and water cement ratio (0.55), the average compressive strength of concrete obtained using fresh and salt water ranges from 27.26-40.80N/mm2 and 24.68 – 39.13N/mm2 respectively while the flexural strength ranges from 6.55-11.13N/mm2 and 6.26-10.76N/mm2 for fresh and salt water respectively. For the mix ratio (1:1.66:4.24) and water cement ratio (0.50), the average compressive strength of concrete obtained using fresh and salt water ranges from 25.05 -38.13N/mm2 and 23.58-36.03N/mm2 respectively while the flexural strength ranges from 6.18-9.88N/mm2 and 6.15 – 10.39N/mm2 for fresh and salt water respectively. The initial and final setting time of cement using fresh water is 50mins and 587mins while that of salt water is 55mins and 605mins respectively

Application of wood waste ash in concrete making: revisited

Portland cement production is a carbon dioxide trigger responsible for almost 5% of the worlds CO2 emissions. Pozzolanic inclusions could contribute to sustainability particularly if they are derived from waste. Managing solid waste is increasingly becoming a global challenge as a result of increasing volume of accumulated waste from industrial and agricultural by-products. Environmental concerns as well as economic implications related with disposal of these wastes have prompted many researches in order to provide viable solutions. Recycling of these waste materials into the construction industry seems to be a more promising and viable alternative most especially in the manufacturing of greener and sustainable concrete material. Wood ash (WA) is a by-product derived from incineration of wood as well as its products such as sawdust, wood bark and chips. This paper presents an overview on investigations performed on the applicability of this material in mortar and concrete making. Specifics on physical, chemical, mineralogical and elemental characteristics of the waste material are discussed. It highpoints the impact of wood ash on workability, compressive and flexure strengths, water absorption, drying shrinkage, carbonation, alkali–silica reaction (ASR) and chloride permeability of concrete