Chemistry is an essential science for understanding and developing construction materials. Specifically, the application of the green chemistry concept to the cement sector may allow the fabrication of new environmentally friendly materials with good sustainability and energy efficiency. Cellular concretes are an excellent alternative to conventional concrete in terms of thermal insulation and material economy. In this paper, the development of waste-based cellular concrete is presented; due to its good performance and low environmental impact, this focus is warranted. Three different cellular concrete systems were investigated: (i) traditional cellular concrete based on ordinary Portland cement and commercial aluminium powder; (ii) geopolymer cellular concrete applying alkali-activated chemical technology with a comparison of the use of two precursors, fluid catalytic cracking catalyst residue (FCC) and blast furnace slag (BFS), and recycled aluminium foil as an aerating agent; (iii) eco-cellular concrete, where commercial waterglass was replaced by an agro-industrial by-product, rice husk ash (RHA), in the activating solution. The development of geopolymer cellular concretes with different precursors and activating solutions has proven that the production of this type of concrete using different types of precursors is possible, depending on the availability of by-products and wastes. The densities, compressive strengths, and thermal properties of the three cellular concrete systems are assessed and a complete study on the carbon footprints of the developed concretes is presented. The results show that the alternative concretes have densities from 474 to 813 kg m⁻³, with compressive strengths from 2.6 to 4.6 MPa and thermal conductivities from 0.083 to 0.281 W m⁻¹ K⁻¹. In the case of the cellular concrete prepared using RHA in the activating reagent, the heat released from the dissolution of NaOH pellets in water dissolved the soluble silica present in the ash. This production method resulted in a reduction of its carbon footprint by 78%.

The degradation of synthetic fibers derived from postconsumer wastes and used in fiber-reinforced cement mortars was studied. Polyethylene terephthalate (PET) and high-density polyethylene postconsumer bottles were immersed in an alkaline medium of a 1-M solution of sodium hydroxide and portland cement paste. Then, the fibers’ surfaces were analyzed by scanning electron microscopy (SEM). This study showed that the fibers have a progressive surface deterioration over time when immersed in either of the two media. Degradation of fibers immersed in pozzolan-portland cement pastes was also observed. The results from the degradation process of these fibers show that it was stronger when they were immersed in the portland cement system ($\mathrm{pH}=12.9$ ), although the pH value was lower than that of the NaOH solution ($\mathrm{pH}=13.8$ ), suggesting that the degradation process in portland cement also depends on the formation of solid hydration products. The preliminary results of this study show overall good behavior of the studied fibers. This behavior generally improves when using pozzolans. Considering that fibers and pozzolans are obtained from wastes, and therefore have low economic and environmental costs, the possibility of using these materials in developing countries should be considered. The use of these wastes would, on the one hand, improve the properties of construction materials, and on the other, enable proper management of waste that could otherwise eventually pollute the environment.

Glass fiber reinforced cement (GRC) is an excellent composite for architects and engineers because it can be molded to produce laminar panels or to create complicated designs. GRC is a fine concrete reinforced with alkali-resistant glass fibers at 3–5% per mass. However, fiber durability is limited because of the aggressiveness of the alkaline medium produced during Portland cement hydration (effect of portlandite). The objective of this study is to assess GRC with high Portland cement replacement with pozzolans (ground fly ash or a mixture of ground fly ash and sonicated silica fume) in order to reduce the corrosion of the fibers. The selected high-content pozzolan (60% replacement) composites were tested under different conditions: aging, drying–wetting, freezing–thawing, and chemical attack (ammonium chloride and sulfuric acid). The modulus of rupture and toughness were determined. Composite behavior showed that the samples with pozzolans not only better resisted aging, but also physical and chemical attacks, and specimens presented a better modulus of rupture and toughness than the samples prepared with 100% Portland cement (control specimens). Due to the good behavior in durability terms, the high pozzolan content GRC products are suitable in potential corrosive environments for sunscreens, drainage channels, cable trays, sound barriers, or pavements.