Role of casting and curing conditions on the strength and drying shrinkage of greener concrete

The shrinkage of cement-based materials is a critical dimensional property that needs proper attention as it can influence the corresponding characteristics especially when the preparation of such cement-based material is done in hot weather. Studies have shown that the casting or curing conditions influence the performance of concrete. However, there is limited understanding of the combined role of casting temperature and curing conditions, especially for concrete made with unconventional binders. In this study, five supplementary cementitious materials (SCMs) were utilized as the substitute of the ordinary Portland cement (OPC) at different ratios to produce greener concrete and improve its characteristics and sustainability. The influence of four casting temperatures (i.e., 25 °C, 32 °C, 38 °C, and 45 °C) and two curing regimes (i.e., covering of samples using wet burlap and applying curing compound on the surface of samples) on the corresponding compressive strength and drying shrinkage at various ages was studied. The outcomes of this research revealed that the composition of the binders has a substantial impact on the characteristics of concrete. In addition, the casting temperature and curing regimes also have a huge role on the compressive strength of concrete produced with binary binders. For example, the compressive strength at 3 days of concrete made at 25 °C made with binary binders was reduced up to 31% compared to that made with only OPC as the binder when cured using wet burlap. Nonetheless, less than 38 ℃ was suitable to minimize the durability issues in the studied blended cement mixes.

     

Phosphorus removal and recovery: state of the science and challenges

Environmental Science and Pollution Research - Phosphorus is one of the main nutrients required for all life. Phosphorus as phosphate form plays an important role in different cellular processes....     

The association between environmental cadmium exposure,blood pressure,and hypertension: a systematic review and meta-analysis

We performed a systematic and meta-analysis study to find the association between cadmium (Cd) exposure and blood pressure (BP)/hypertension (HTN) in exposed general populations. We searched main databases for literature published between year 2000 and April 15, 2021. Quality assessment was performed with the Joanna Briggs Institute (JBI) critical appraisal tools. Heterogeneity between studies was determined by I-squared (I²) statistic. The random effects model was used to determine the association between blood and urine Cd levels with hypertension. The overall standard differences in mean for Cd level in hypertensive and control groups were 3.34, 1.79, and 8.09 based on samples from blood, urine, and hair, respectively. The overall standard differences in mean for Cd level in the low and high exposure groups were???0.795 and???1.036 based on blood and urinary samples, respectively. Our findings indicate a positive relationship between blood and hair Cd levels and hypertension. We also found that hair is the optimal biological sample to find the relationship between Cd exposure and hypertension for both genders. However, more studies are needed to confirm these findings.

     

Heterogeneous impacts of environmental regulation on foreign direct investment: do environmental regulation affect FDI decisions?

Environmental Science and Pollution Research - The industry selection effect occurring from the impact of environmental regulation on foreign direct investment (FDI) in China is heterogeneous....     

Experimental study on fresh,mechanical properties and embodied carbon of concrete blended with sugarcane bagasse ash,metakaolin, and millet husk ash as ternary cementitious material

Environmental Science and Pollution Research - In recent years, the research direction is shifted toward introducing new supplementary cementitious materials (SCM) in lieu of in place of Portland...     

Wetting mechanism and morphological adaptation; leaf rolling enhancing atmospheric water acquisition in wheat crop—a review

Environmental Science and Pollution Research - Several plant species such as grasses are dominant in many habitats including arid and semi-arid areas. These species survive in these regions by...     

Taurine modulates dynamics of oxidative defense,secondary metabolism,and nutrient relation to mitigate boron and chromium toxicity in Triticum aestivum L. plants

Environmental Science and Pollution Research - The present study was undertaken to appraise the efficacy of exogenous taurine in alleviating boron (B) and chromium (Cr) toxicity. Taurine protects...     

Does economic complexity lead to global carbon emissions convergence?

Environmental Science and Pollution Research - This study examines how economic complexity, along with human capital, total factor productivity, foreign direct investment, and trade openness, leads...     

The ameliorative effect of kaempferol against CdCl2- mediated renal damage entails activation of Nrf2 and inhibition of NF-kB

Environmental Science and Pollution Research - This study evaluated the nephroprotective effect of kaempferol against cadmium chloride (CdCl2) -induced nephropathy in rats. It also investigated if...     

Introducing artificial intelligence to the radiation early warning system

Environmental Science and Pollution Research - Although radiation level is a serious concern which requires continuous monitoring, many existing systems are designed to perform this task. Radiation...