The effect of curing condition of five different composition of Portland composite cement (PCC) and ordinary Portland cement (OPC) were investigated in this study. Compressive strength development of five different concrete types has been investigated in terms of cement content and curing duration. From the experimental observation, it is found that the early age strength of concrete made with PCC is lower than that of concrete made with OPC due to the presence of fly ash in PCC which is responsible for the pozzolanic reaction. The continued pozzolanic activity of fly ash contributes to increase strength gain at later ages at continued curing condition. It is also found that drying ambient conditions reduction of the strength potential of concrete made with PCC because the secondary (pozzolanic) reaction fails to contribute to the development of strength.
Reinforced concrete (RC) frames with an open ground floor and various infill distributions have been analyzed for seismic loadings by the finite element method. The infills have been modeled by diagonal struts. Focus is placed on the effects of infill distribution on various structural responses, including (i) the lateral deflection, (ii) the column axial forces, (iii) the column bending moments, (iv) the base shear, and (v) the natural period of the frame. The equivalent static force method (ESFM) and response spectrum method (RSM) for linear structures have been applied, and the results obtained have been compared. It was found that the structural responses do not change appreciably by the ESFM analysis for random infill distributions, while they increase noticeably in the RSM analysis. This manifests the inadequacy of using the ESFM for general purposes, for which modifications were proposed in this paper for the design of RC columns. As the natural period of the RC frame converges with the code equations only for higher amounts of infill, it is necessary to incorporate the amount and distribution of infill in the dynamic analysis of RC frames.
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