The use of waste as supplementary cementitious materials (SCMs) in concrete is already widespread, with glass waste being an increasingly used option. The utilization of glass waste as a partial substitute for cement in small proportions has shown satisfactory outcomes. Nevertheless, substituting cement in high proportions requires further investigation. Experimental research was carried out on the mechanical and durability properties of concrete with the replacement of cement by glass powder (GP), at a high volume equal to 50%. Binder content (cement plus GP) varied from 300 to 500 kg/m³. The results are promising regarding the use of the high volume of GP in high-performance concretes. The specimens with 500 kg/m³ of binder (50% of which was GP-G250) achieved almost 55 MPa at 28 days. The specimen with the lowest resistance was G150, with 32 MPa. This result may be related to the high pozzolanic activity index of the used GP. The specimens with GP showed satisfactory performance regarding chloride migration, with diffusion coefficients always below those of the reference specimens. The G250 concrete showed a reduction of 58%. Regarding open porosity, concretes with 50% GP had a lower porosity than the reference concretes. The smallest reduction (21%) occurred in the G150 concrete. The reduction in porosity provided by the fineness of the GP may be the main cause of this high performance. Concerning capillary absorption, the GP concretes have a reduction that varies between 47% for G150 and 67% for G250. This fact may be related to the existence of a larger quantity of larger-sized capillary pores in the reference concretes.

The high consumption of concrete makes it a priority target for environmental goals. When supplementary cementing materials were introduced, important progress was made toward achieving these goals, with fly ash (FA) making a major contribution in this regard. Given the current situation, it has become necessary to identify an alternative to this material as a result of the shutdown of coal-fired power plants across the European Union. In this sense, glass powder (GP) has shown promising results. This research focused on reducing the dosage of Portland cement (PC) as extensively as possible in concrete formulations, through high incorporations (until 70%) with different dosages of binder to evaluate various applications without compromising its strength and durability. The results obtained are encouraging. With only 150 kg/m³ of PC, 46.42 MPa was obtained, and with 250 kg/m³ of PC, 71.50 MPa was obtained, both at 90 days. Durability was not significantly compromised in the tests carried out and even obtained better results in some tests. The findings suggest that a substantial replacement of PC with GP could serve as a feasible option for lowering the PC content or even substituting FA, promoting a reduction in CO₂ emissions and energy consumption, and making concrete more sustainable.

O desenvolvimento mundial impulsiona a procura por cimento e os desafios ambientais associados à sua fabricação preocupam os investigadores. O setor de cimento é o terceiro maior consumidor industrial de energia e o segundo maior emissor de CO₂. Neste sentido, algumas medidas têm sido implementadas. Para além da redução da relação clínquer/cimento, a redução do consumo de cimento através da utilização de Materiais Cimentícios Suplementares em substituição parcial do cimento é uma estratégia eficiente e atual. O uso de resíduos industriais como, por exemplo, as lamas provenientes do corte de rochas ornamentais, tem sido uma aposta que favorece, também, a economia circular. Neste sentido, foi desenvolvida uma pesquisa experimental com o objetivo de avaliar o comportamento de argamassas cuja composição utiliza lamas provenientes do corte de rochas ornamentais produzidas em Portugal, nomeadamente, travertino, gabro, granada e basalto. Foram estudadas propriedades das argamassas no estado fresco e endurecido após 28 e 90 dias de cura. O índice de atividade pozolânica foi determinado. Os resultados sugerem um desempenho satisfatório face às argamassas de referência. As lamas estudadas promovem a economia circular e têm potencial para se apresentar como substituto parcial do cimento na produção de materiais cimentícios com utilizações específicas.

The use of supplementary cementitious materials (SCM) can enhance concrete durability. Fly ash (FA) has been used as SCM, especially in chloride-rich environments, but its availability is decreasing due to the closure of coal-fired power plants in EU countries such as Portugal. Glass powder (GP) emerges as a promising alternative because of its suitable chemical composition and wide availability. To evaluate concrete performance with high GP incorporation, specimens with different binder contents were produced using 50 % of SCM, either FA or GP. Mechanical and durability properties were evaluated, besides their environmental impact. Results showed that concretes with high GP incorporation are chloride-resistant and can be a potential substitute for FA. GP250-50, using 250 kg/m3 of cement, had lower chloride diffusion coefficients than the reference and FA concretes. At 90 days, the reduction was 91 % and 35 %, respectively. Furthermore, they had a significant CO₂ emission reduction (16 %), confirming their sustainable potential.