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In emerging countries, the driving elements for sustainable development are greenhouse and global warming concerns and the need for the development of low-CO2 cements as replacement for Portland cement. Pumice is an aluminosilicate-type material that can be condensed with NaOH and Na2SiO3 solution and can be used for green building with reduction in CO2 footprint. The present paper highlights the effect of curing temperature on Hasankale pumice activation. Four curing temperatures have been investigated in this paper, 25°C, 45°C, 65°C, and 85°C, and 65°C has been confirmed as the best temperature for ground pumice activation. Furthermore, the aging effect has been studied at different curing temperatures. The aging of the samples before 28 days has a remarkable effect on compressive strength gain, but after 28 days this effect is inconsiderable for all heat treatment temperatures.

Determining a feasible safety factor for space trusses is an important phase in structural analysis that could have economic benefits. We know there are many kinds of imperfections in structural elements, which include both material and geometric flaws. Predicting factual behavior of structures is very difficult and occasionally impossible. Elements with initial geometric imperfections in space trusses are a common phenomenon, in addition, equivalent initial geometric imperfections can be applied for modeling of residual stresses or eccentric loading effect. The number of members in the space structures is usually high as is the diversity in the kind of initial imperfection. Therefore, there is a high likelihood that models must be analyzed. The structure must be analyzed with non-linear methods, making these approaches time consuming, and potentially uneconomical. In this study, we selected 30 cases for random analysis based on Monte Carlo methods to find the bearing capacity of the space truss. We attained results from the LUSAS program LUSAS Modeller, Version 13, UK program and these were then exported as input data to the Artificial Neural Network (ANN) program. A reasonable neural network has been found of predicting another 30 cases for load bearing capacity without any analysis and only based on the neural network program. Finally, a new approach for determining the load capacity of the space trusses was extracted and we predicted the occurrence possibility of the convenience load bearing capacity in 60 cases.

This paper studies the influence of two admixtures on expanded perlite aggregate concrete. Both silica fume and fly ash were added as replacement for cement by decreasing the cement weights in the ratios of 10, 20 and 30% by weight. The binder dosage was kept constant at 200 kg/m3 throughout this study. Superplasticizer was used 1.5% by weight of Portland cement to reduce w/c ratios.The obtained results showed that: the thermal conductivity decreased with the increase of silica fume and fly ash as replacement for portland cement up to 14 and 18%, respectively. Densities of all samples decreased from 522 to 483 kg/m3 with the increase of both admixtures. Silica fume and fly ash decreased the density of samples. The compressive strengths decreased 12, 19, 29 for 7 days, and increased 9, 13%, 4%, for 28 days due to 10, 20 and 30% silica fume, respectively. Fly ash induced to reductions in the compressive strength up to 36% at 7 days and 27% at 28 days. [Copyright &y& Elsevier]

Cement paste with natural sand content and the effect of silica fume (SF), class C fly ash (FA) and blast furnace slag (BFS) on the thermal conductivity and compressive strength of mortar was investigated. SF, FA and BFS were added as replacement for cement by decreasing the cement in the ratios of 10, 20 and 30% by weight.The maximum thermal conductivity of 1.186 W/mK was observed with the samples containing plain cement. It decreased with the increase of SF, FA and BFS as replacement for cement. The reductions due to SF were 17, 31 and 40% for 10, 20 and 30% SF (replacement for cement), respectively. FA induced reductions of 14, 26 and 33% for 10, 20 and 30% FA, respectively. Both SF and FA had a decreasing effect on thermal conductivity. BFS effect on the thermal conductivity, was approximately the same at all percent (BFS replacement for Portland cement, PC) and the reduction values were between 12 and 14%. Ten percent SF and 10 and 20% FA and all level BFS increased compressive strength a little at 120 days. However, except 10% SF the other admixters at all level replacement decreased compressive strength at early ages, especially FA decreased compressive strength as function of replacement percent. [Copyright &y& Elsevier]