The common cause of cracking in cement paste is shrinkage due to different reasons, such as loss of water and chemical reactions. Incorporating limestone fines (LF) as a cement replacement can affect the shrinkage of the paste. To examine this effect, five paste mixes were prepared with 0, 5, 10, 15 and 20% LF as a cement replacement and with a water-to-binder ratio (w/b) of 0.45. Four volume stability tests were conducted for each paste: chemical, autogenous and drying shrinkage and expansion. Chemical shrinkage was tested each hour for the first 24 h and thereafter every 2 days for a total period of 90 days. The drying shrinkage, autogenous shrinkage and expansion were monitored every 2 days until 90 days. The results showed that replacing 15% LF enhanced the chemical shrinkage of the paste. However, autogenous shrinkage of the paste was found to increase between 0 and 10% LF and decline sharply at 15 and 20% LF. Drying shrinkage was found to increase with the increase in LF content. Expansion exhibited little variation between 0 and 10% LF and an increase for replacement above 15% LF. These results are discussed in terms of the formation of hydration products and self-desiccation due to hydration.

The main aim of this study is to examine the effect of incorporating limestone nes (LF) on chemical shrinkage of pastes and mortars. For this purpose, ve paste and ve mortar mixes were prepared with 0, 5, 10, 15 and 20% (by weight) LF as replacement of cement. The water to binder ratio (w/b) was 0.45 for all mixes. The sand to binder (s/b) ratio in the mortar mixes was 2. Testing included chemical shrinkage, compressive strength, density and ultrasonic-pulse velocity (UPV).Chemical shrinkage was tested each hour for the rst 24 hrs, and thereafter each 2 days until a total period of 90 days. Furthermore, compressive strength and UPV tests were conducted at 1 day, 7, 28 and 90 days of curing. The results show that the long-term chemical shrinkage of pastes was found to increase with the increase in LF content up to 15%. Beyond this level of replacement, the chemical shrinkage started to decrease. However, the chemical shrinkage for mortars increased with the increase in LF content up to 10% LF and a decrease was observed beyond this level. It was also noticed that compressive strength for pastes and mortars attained the highest value for mixes containing 10 and 15% LF. The trend in the UPV results is somewhat similar to those of strength. Density for pastes and mortars increased up to 15% LF followed by a decrease at 20 % replacement level. Correlations between the various properties were conducted. It was found that an increase in chemical shrinkage led to an increase in compressive strength.

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Nowadays, hot weather is an essential motivator that leads concrete to lose its special characteristics. The high loss of moisture by evaporation and rapid hardening encourage the cracking potential and placement operations. The fresh mixed and hardened concrete tend to be damaged due to several conditions such as: high concrete temperature, High ambient temperature, low relative humidity, and high wind speed. These circumstances accelerate the rate of moisture loss and cement hydration. This article briefly reviews hot weather concreting problems precautions, and curing methods and also discusses the role of incorporation SCMs in reducing the temperature of concrete and enhancing its mechanical and durability performance.

The construction industry has seen a growing emphasis on the use of sustainable materials in recent years. This is driven by various factors, including a desire to reduce environmental impact, improve indoor air quality, and promote the health and well-being of building occupants. One sustainable material that is being increasingly utilized in construction is natural fibers. Phragmites australis fibers, in particular, are renewable, biodegradable, and have a low carbon footprint. The present study aims to evaluate the impact of Phragmites australis fibers on the behavior of reinforced concrete beams. Five concrete mixes were utilized in the experiment, with the control mix having a 1:1.5:3 ratio of cement to sand to coarse aggregate by weight. The other four mixes incorporated Phragmites australis fibers at 0%, 0.5%, 1%, and 1.5% of the volume of the mix, with cement replaced by 10% glass by weight. The water-to-cement ratio was set at 0.4 for all mixes. Concrete cubes, cylinders, and prisms were prepared to determine mechanical and physical properties, while reinforced concrete beams were used to assess structural performance. The results of the experiment showed that the addition of Phragmites australis fibers slightly decreased the compressive and tensile strength of the concrete compared to the control mix. However, the inclusion of 0.5% Phragmites australis fibers enhanced the split tensile and flexural strength of the concrete. In terms of reinforced concrete beams, the maximum load-bearing capacity was realized for the mix with 10% glass and 0% Phragmites australis fibers. However, the highest ductility index and deflection were achieved for the mix with 10% glass and 0.5% Phragmites australis fibers. Therefore, the use of Phragmites australis fibers can improve the structural performance of concrete.

The main aim of this study is to examine the effect of incorporating limestone fines (LF) on chemical shrinkage of pastes and mortars. For this purpose, five paste and five mortar mixes were prepared with 0, 5, 10, 15 and 20% (by weight) LF as replacement of cement. The water to binder ratio (w/b) was 0.45 for all mixes. The sand to binder (s/b) ratio in the mortar mixes was 2. Testing included chemical shrinkage, compressive strength, density and ultrasonic-pulse velocity (UPV). Chemical shrinkage was tested each hour for the first 24 hrs, and thereafter each 2 days until a total period of 90 days. Furthermore, compressive strength and UPV tests were conducted at 1 day, 7, 28 and 90 days of curing. The results show that the long-term chemical shrinkage of pastes was found to increase with the increase in LF content up to 15%. Beyond this level of replacement, the chemical shrinkage started to decrease. However, the chemical shrinkage for mortars increased with the increase in LF content up to 10% LF and a decrease was observed beyond this level. It was also noticed that compressive strength for pastes and mortars attained the highest value for mixes containing 10 and 15% LF. The trend in the UPV results is somewhat similar to those of strength. Density for pastes and mortars increased up to 15% LF followed by a decrease at 20 % replacement level. Correlations between the various properties were conducted. It was found that an increase in chemical shrinkage led to an increase in compressive strength.

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