Influence of the curing temperature on the properties of poly(phospho-ferro-siloxo) networks from laterite

Abstract

The main objective of this work is to investigate the influence of the curing temperature on the properties of poly(phospho-ferro-siloxo) networks using laterite as an aluminoferrosilicate source and phosphoric acid as a hardener. Poly(phospho-ferro-siloxo) networks were obtained by mixing phosphoric acid with calcined laterite and the fresh specimens were cast in different moulds. The prepared specimens were cured at room temperature, 40, 50, 60, 70, 80 and 90 °C for 24 h and then maintained at an ambient atmosphere of the laboratory for 28 days. The poly(phospho-ferro-siloxo) networks cured at room temperature were demoulded after 3 days due to its low rate of the hardening process. The obtained poly(phospho-ferro-siloxo) networks were characterized by measuring the compressive strengths, apparent density, X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The results show that the values of the compressive strengths of the final products decrease from room temperature (83 MPa) to 40 °C (48 MPa) and increase from 40 to 50 °C (65 MPa) afterwards decrease from 50 to 90 °C (24 MPa). It was found that the highest value of the compressive strength of poly(phospho-ferro-siloxo) network is around 83 MPa corresponding to the specimen demoulded after 3 days and maintained at room temperature for 28 days. Whereas, when the polycondensation reaction is accelerated, the most convenient curing temperature is around 50 °C which belongs to a compressive strength at about 65 MPa.

Amorphous phase of volcanic ash and microstructure of cement product obtained from phosphoric acid activation

“…12a, b). Also, the fact that the maximum amount of iron and aluminium are differents (0.3 mol for Fe and 0.2 mol for Al) suggest their reaction with phosphorus atoms and their participation in the formation of product as observed by Bewa et al [28] for laterite based geopolymer phosphate and Tckakouté et al [26] for metakaolin based geopolymer phosphate. This participation of iron explain their great dissolution in acid medium (Table 2).…”

“…The main drawback for the synthesis of magnesium phosphate cement is the high cost of magnesia. Acid activation is also used for the synthesis of phosphate based calcined clay cements [25][26][27][28][29][30][31]. In this case, maintaining the reactive medium at 60 °C is generally helpful to get reliable cements [25-27, 29, 32-36].…”

Control of the setting reaction and strength development of slag-blended volcanic ash-based phosphate geopolymer with the addition of boric acid

“…The reaction products as demonstrated in the literature are generally amorphous with a polymeric-like structure consisting mainly of repeating units of silicophosphate, aluminophosphate, silico-aluminophosphate, ferro-silicoaluminophosphate, and etc. [3][4][5][6]. Wagh suggested that because of the 3-dimensional structure of some of those phases along with their amorphous polymeric structure, APC should be called phosphate geopolymer [7].…”

Physical and Mechanical Properties of a Porous Material Obtained by Low Replacement of Volcanic Ash by Aluminum Beverage Cans

“…Additionally, the band at 990 cm -1 is most of time assigned symmetrical bending of the Si-O-T bonds [23], and Fe-O-Si when the solid precursor contains a significant amount of Fe 2 O 3 [24,25,26]. On the other hand, the band located at 1649 cm…”

“…The first region shows the peaks of the weak absorption bands located at 615, 683, 747 and 990 cm -1 which characterize the stretching and bending vibrations of the Si-O-T bonds (T: Si, Al or Fe [17,18,19]. In fact, many authors show that the peaks around 615 cm -1 can also be attributed to the vibrations of the stretching and bending of the Fe-O bonds of hematite or other iron oxide rich minerals [17,20,21] while that at 747 cm -1 characterizes the vibration modes of the Si-O bonds of the silicate network [22,23].…”