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In real applications, 28 days are regarded as proper curing time for concrete. There is a self-evident need to minimize the duration of curing days. For this purpose, this research investigates 1 to 7 days of curing and compares it with concrete cured for 28 days. Three grades of normal concrete strength grade 30, grade 35 and grade 40 were made. After curing, two exposure conditions were applied to the concrete, inside laboratory-controlled environment and outside environment. Results indicate that slump increases with cement content in DOE method at constant water content. The concrete density in all grades reduces when the concrete is subject to inside exposure in comparison with outside exposure. Water loss from concrete reduces with increase in curing days in all concrete grades. Compression strength of all concrete grades increases with increase in curing days. For the uniformity of concrete, ultrasonic pulse velocity indicated that with an increase in curing days, concrete becomes denser and a bit void. Results showed that an increase in curing days also improves the surface quality of concrete. The significance point noticed is that there was not much difference in the concrete properties between 7 days of curing and 28 days of curing in all grades.

Wood yields a number of by-products and Sawdust is as useful as others. Sawdust is regarded as a waste material and is effectively utilised as sawdust concrete in the construction of buildings. It is capable to be utilised as light-weight concrete and holds the quality of long duration heat transfer. In this study, three different ratios (1:1, 1:2 and 1:3) volume mix proportions of cement to sawdust were adopted to make sawdust concrete. At varied intervals of 7, 28 and 56 days of air curing, thermal and mechanical properties like workability, density, elastic modulus, strength and heat transfer were probed of mentioned sawdust concrete proportions. The resistance to elevated temperatures was also evaluated after 28 days of age; weight loss, residual compressive strength, surface texture and ultrasonic pulse velocity were considered in evaluation process. The findings showed that increase in sawdust volume affected to decrease the workability, strength and elevated temperatures resistance. However, the concrete having higher proportion of sawdust performed competently and well in terms of thermal conductivity. Moreover, a decrease in the heat transfer of sawdust was also observed. Examining the all-embracing mechanical and physical properties, sawdust can be effectively utilised in the construction of buildings.

Industrialization in developing countries has resulted in an increase in agricultural output and consequent accumulation of unmanageable agro wastes. Pollution arising from such wastes is a matter of concern for many developing nations. The aim of this study is to investigate the behavior of lightweight concrete and the utilization of sawdust as waste material in concrete. This paper focuses on the manufacturing of concrete which possess long duration heat transfer by using sawdust waste. In this research, cement to sawdust ratio of 1:1, 1:2 and 1:3 by volume was prepared for sawdust concrete, and the ratio of sand was kept constant that is 1. At these ratios, the mechanical and thermal properties like density, workability, strength and heat transfer were measured after, 7, 28 and 56 days of air curing. The tests results show that with the increase in the amount of sawdust, the workability, compressive strength, tensile strength and flexural strength decreased. It also resulted in reduction of heat transfer of sawdust concrete. Taking into account the overall physical and mechanical properties, sawdust concrete can be used in construction technology.

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The primary reason for the curing of concrete is to complete the hydration reactions of cement with other materials. However, the problem occurs when required ideal curing becomes challenging due to various anomalous structural elements. To mitigate this issue, a bacterial solution known as Effective Microorganism (EM) has been introduced as a self-curing agent that has favourable surface tension, viscosity and solubility in water. Different percentage of water i.e. 0%, 5%, 10%, 15%, 20%, and 25% were replaced with EM. The optimisation of percentage replacement of EM was based on the compression strength and water loss of concrete. The percentage of EM with 10% water replacing showed better compression strength as compared to other percentage replacements. With the optimum 10% percentage, compression strength was found 42 MPa and 49 MPa compared with 33 MPa and 43 MPa with control samples with air and water curing respectively. The water loss also reduced 2% with 10% EM replacement compared to the control sample. Results showed that 10% of EM is the optimum value to get desirable properties of concrete in air and water curing. EM can be used as a new self-curing agent as a novel approach in the area of self-curing concrete.

The aim of this study was to shows the behavior of sawdust concrete at elevated temperature. Sawdust is considered as waste material but nowadays this waste material is utilized in the construction of the building as sawdust concrete. Sawdust is a by-product of wood which is generally used in the production of lightweight concrete, possessing low thermal conductivity. In this study sawdust concrete was made at three different proportions of cement and sawdust 1:1, 1:2, 1:3 by volume. At these proportions, the physical and mechanical properties such as density, workability, strength, fire resistance, mass loss, ultrasonic pulse velocity and residual strength were investigated after 28 days of curing. It was found that with the increment in the amount of sawdust, the workability and strength decreases, however in terms of fire resistance, concrete with lower amount of sawdust performed well. Considering the overall physical and mechanical properties, sawdust concrete can be used in building construction.

In practical applications, problems related to proper curing arise for inclined structural elements, especially in skyscrapers, wherein concrete is very thick. To overcome this problem, the implementation of self-curing technology using varieties of smart materials has become significant. Based on these factors, this study determined the impact of effective microorganisms (EMs) as a new self-curing agent on the microstructures and strength properties of sustainable concrete. Five concrete mixtures were prepared with various EM content (5, 10, 15, 20, and 25%) as water replacement under air-curing condition. The workability of the concretes was found to increase with the increase in EM contents from 0 to 25%. In addition, concrete designed with 10% of EM achieved the highest compressive strength (42 MPa) after 28 days of aging as opposed to the control specimen (35 MPa). The microstructures of the concrete made with 10% of EM revealed very a compact network, fewer voids, and formulation of dense C-S-H gel. Based on the results, the proposed EM may be implemented as a self-curing agent to achieve high-performance sustainable concretes beneficial for the construction sectors.