Concrete Research Letters
[3 followers] Follow
Open Access journal
ISSN (Print) 2180-1371
Published by ISSR Journals [3 journals]
- Microbial deterioration effect of cow dung ash modified concrete in
Authors: Vinita Vishwakarma
Pages: 84 - 97
Abstract: This paper explain the microbial deterioration of normal concrete (NC) and concrete modified with cow dung ash (CDA) in freshwater environments. Five different concrete mixes of M30 grade were prepared by replacing ordinary portland cement (OPC) with 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0% CDA by weight of cement and were compared with NC (0% CDA). First the antimicrobial properties of CDA powder were evaluated. All the specimens were cured for 28 days and then exposed in fresh water for 45 days to identify the best mix of concrete. pH degradation studies on the exposed samples were evaluated. Total viable bacterial counts (TVC) studies revealed that microbial growth was less in CDA modified concrete as compared to NC. Total dissolved solids (TDS) and Total suspended solids (TSS) were done to know the inorganic and organic content in the biofilm sample. Epifluorescence microscopic observation showed less number of fluorescing cells indicated the inhibition of biofilm formation on CDA modified concrete. XRD analysis was done to find the changes in the crystalline phases within the modified concrete microstructures and its antibacterial activity.
Issue No: Vol. 7, No. 3 (2016)
- The Effect of Different Mineral Admixtures on Characteristics of Concrete
Authors: Salahaldein Alsadey Mohamed
Pages: 98 - 103
Abstract: This paper presents a review of the properties of fresh and hardened concrete by using mineral admixtures fly ash (FA), and silica fume (SF). In many countries, these materials are already used in manufacturing of concrete. However, these industrial by products is becoming popular throughout the world because of the minimization of their potential hazardous effects on environment. Some of these materials used as replacement for cement. Ultimately it results in the reduction of the cost manufacturing of concrete and reduces environmental pollution. In general, small particle size and higher specific surface area of mineral admixture are favorable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water. To study the effect of mineral admixtures such as fly ash and silica fume on mechanical properties of concrete under the uniaxial compression experimental studies conducted. The cement was replaced by 10 %, 20 % and 30 % with fly ash and silica fume. The compressive strength test conducted on concrete specimen with different percentages of fly ash and silica fume at age of 7 days and 28 days.
- Empirical Model for Evaluation of Concrete Corrosion Current Density
Authors: Saha Dauji
Pages: 104 - 112
Abstract: In health evaluation of existing concrete structures, the state of reinforcement corrosion needs to be ascertained without causing distress to the structure, and one indirect approach is to correlate the resistivity of concrete to the corrosion current density and thus to the corrosion. Three models reported in literature are analyzed in this paper for their accuracy, and a new approach with different models for different ranges of resistivity are proposed which performs with better accuracy. The strengths and the limitations of the different models are discussed.