چكيده به لاتين
Abstract
The main purpose of this study is to develop and characterize an inorganic polymeric binder by activating phosphorus slag. For this purpose, at first, phosphorus slag was activated using various activators and as needed, efflorescence was controlled by application of hydrothermal conditions and addition of high alumina cements. Then, based on compressive strength and efflorescence formation severity data of paste specimens and also taking into account the price factor, two of the most optimum compound activators including; NaOH+Na2CO3 and Na2CO3+Ca(OH)2 were selected for investigating their effects in activation process using adiabatic calorimetry data. In the next step, the optimal formulations of mortar for the two selected activators were developed and the influence of curing conditions on the activation of phosphorus slag, reaction kinetics, and durability of mortar specimens at pH 2 of hydrochloric and sulfuric acids were studied. The amount of adiabatic heat generated by the activation of phosphorus slag using NaOH, NaOH+Na2CO3 and Na2CO3+Ca(OH)2 activators for 72 h were 250, 507 and 213 J/g, respectively. Based on the obtained results, mortar specimens activated with the selected low-cost compound activators of NaOH+Na2CO3 and Na2CO3+Ca(OH)2 exhibited 28-day compressive strengths of 52 and 55 MPa, respectively, with no efflorescence formation. Curing conditions showed a significant effect on both molecular and microscopic structures of the binder and its mechanical properties. The order of activation reaction rate was determined as second and independent of the type of activator, but different apparent activation energies of 35.6 and 60.7 kJ.mol-1 were determined for NaOH+Na2CO3 and Na2CO3+Ca(OH)2 activators, respectively. Durability tests showed that activated phosphorus slag mortar specimens were deteriorated at a slower rate in acidic environment compared to Portland cement mortar specimens.
Keywords: Phosphorus slag, Inorganic polymer binder, Activator, Kinetics, Calorimetry
