A study was undertaken to produce lightweight aggregate concrete using artificial lightweight aggregate (Lytag) made from sintered fly ash. Cement or fly ash-based geopolymer was utilized as binder material, and its effect on the properties (compressive strength, water absorption, and thermal conductivity) of lightweight aggregate concrete was investigated. Two mixes were designed (using the absolute volumes method) and produced at a density of around 1350 kg/m3 as cement lightweight aggregate concrete and geopolymer lightweight aggregate concrete. Fly ash and an alkaline solution (sodium hydroxide and sodium silicate) were used to produce the geopolymer paste. The results indicated that the compressive strength, water absorption, and thermal conductivity of lightweight aggregate concrete made with geopolymer paste were better than those made with cement paste. An increase in compressive strength by about 49% and a decrease in water absorption and thermal conductivity by about 36% and 25%, respectively, were noticed in fly ash-based geopolymer lightweight mix compared to cement lightweight concrete mix.
Determining building materials and their types and determining their effect on concrete properties are consistent with the technical and design variables of buildings. From this point of view, the research came to include theoretical studies and empirical tests for some materials, focusing on the aggregate as a basic material involved in the formation of concrete. The first part includes the introduction, research problem, assumptions, importance, and purpose of the research. the second part was to conduct practical experiments by designing different concrete mixtures in the mixing ratios and the type of aggregate until results were reached regarding the resistance of the concrete that was produced as a result of the difference in densities between ordinary aggregate concrete and lightweight aggregate concrete. Through that, for example, the lightweight aggregate with an age of (7) days and a mixing ratio of (1: 2: 4) gave strength to the models used (19.58) Mpa, and for the same mixing ratio and at an age of (28) days, it gave durability ( 22.83) Mpa. When the mixing ratio was changed to (1: 1.5: 3), it was (25.74) MPa and (32.34) MPa at the age of (7) days and (28) days, respectively. These results give an accurate indication that the aggregate is light in weight with similarity to the ordinary aggregate in obtaining concrete with a bearing strength within the approved specifications without guaranteeing the environmental treatments and the resulting loads
The aim of this research is to produce lightweight cement mortar with properties better than reference ordinary cement mortar. Porcelanite stone were utilized as lightweight aggregate with a volumetric partial substitution of fine aggregate. The process includes using different percentages (5, 10, 15 and 20 %) of pre-wetted (24hr.) porcelanite to produce lightweight mortar with internal curing. Water curing was used for reference mortar mixture and air curing for the other mixtures of porcelanite substitution. Compressive strength, flexural strength, density and ultrasonic pulse velocity for different ages (7, 14 and 28 days) have been tested. The results show an improvement in the properties of cement mortar especially in replacement percentage of 10 %.