Lightweight structural thermal insulation concrete using TPP ash

The article presents the results of developing lightweight structural concretes based on ash-slag waste from the Almaty Thermal Power Plant-2. The ash-slag aggregates were produced using both firing and non-firing (clinker) technologies. The fired aggregates, obtained with the use of bentonite clay, exhibited a bulk density of 530–640 kg/m³ and a strength of 1.8–4.8 MPa. The non-fired aggregates based on Portland cement had a density of 644–690 kg/m³ and a strength of 1.79–2.98 MPa, while those based on liquid glass showed a density of 562–642 kg/m³ and a strength of 1.93–3.8 MPa. Using the obtained aggregates, lightweight concretes with a density of 1210–1750 kg/m³ and a strength of 100–152 kg/cm² were produced, meeting the requirements of GOST 25820-2014. In the compositions without coarse aggregate, the influence of additives such as CaCl₂, superplasticizers, and basalt fibers on the properties of ash concrete was studied. The strength of the concrete after 28 days exceeded the 7-day strength by 1.5–2.3 times, with the most significant effect observed from CaCl₂. Ash concrete of classes B10–B12 with a density of 1500–1600 kg/m³ was obtained, which according to GOST can be classified as structural-thermal insulating concrete. The objective of the research is to develop compositions of lightweight structural concrete based on ash-slag waste. The novelty of the work: for the first time, ash-slag aggregates based on the ash-slag from Almaty Thermal Power Plant-2 have been obtained using both firing and non-firing technologies.